Page images
PDF
EPUB

to be found, while in Darwinella, triaxon horny spicules means unlikely that the sponges may exclusively abu abound.

liquid food—that is to say, organic substances díssure Very interesting accounts are given of the connective in the water which is continuously passing through the tissue, muscle cells, and nervous system. Stewart's canal system. All the other organisms in which arrez account of the "palpocils” is accepted ; and, although ments are made to insure a continuous water curre Prof. Stewart's specimens are the only ones which show I refer to the higher plants-absorb exclusively nourisha these organs properly, yet Lendenfeld thinks that, when material in solution (the absorption of gaseous ford groups of converging sense-cells are observed in sections) plants does not concern us here). The existence and below the continuous surface, these may be regarded as traversing canal system and a continuous water crure the cells of a “retracted” palpocil.

seems to me to point to the nourishing material The researches of the author have thrown but little sponges being in solution in the sea-water. The numero fresh light on the subject of the occurrence of the strange fine sieves and filter arrangements generally, and the me “filaments” in the species of the genus Hircinia ; these fact that the water always enters through the smaller hol filaments are generally more abundant in the superficial and is expelled through the larger, clearly shows that the layer than in the interior of the sponge. They may be sponges are not desirous that large food-particles shoe isolated, or arranged in bundles of varying thickness, in enter their canal system." which they are parallel. Such bundles are particularly Even granting that the word " exclusively" should conspicuous in H. gigantea, where they form a pretty after the word “material,” we do not quite understur uniform network which pervades the whole of the sponge. the comparison of the well-known facts of plant physio The filaments are never straight: they may be continuously as they are presented to us in the above extract, nor and simply curved, or they are undulating. The latter form how it helps us to an understanding of how the sp of curvature is particularly frequently observed in the adds to its protoplasm ; the undoubted power posses filaments which are joined to form large bundles. While by some of the sponge-cells to lay down silica, lime, &c. their abundance is subject to variation, no case of a quite different functionally from the phenomena attends sponge with but a few isolated filaments is on record. No growth and development, using these terms in Herne apparent young stages of these filaments have been seen. Spencer's sense ; but once set a thinking, our auk Schulze's researches enabled him to make no positive proceeds, and telling us that a "tape-worm is an ann statement concerning them, but they at the same time which takes up liquid food, and which has no speci demonstrated that “no cellulose is contained in them, digestive apparatus, and that it evidently takes up a gre that they have no trace of true cellular structure, and quantity of material from the surrounding chyle thro that they contain a great deal of nitrogen (92 per cent. of the apparently indifferent cylindrical ectodermal ep::b their substance), and that they are not Algæ. The resist- lium cells; that the excess material and waste produs ance of the filaments in boiling alkali is against their are got rid of by the nephrydia," he goes on 10 being ordinary Fungi, while their general chemical com- that he is inclined “ to think that in sponges we may ha position indicates no relationship to the ordinary sponge a similar mode of absorption of nourishment”; but the skeleton.” As to the very minute dumb-bell shaped struc- where are the nephrydia or their analogues ? and tures observed by Poléjaeff, and considered by him to be thinks again " that it is not impossible that the cilin young stages of the filaments, Lendenfeld thinks that this chambers may be partly analogous to the nephryda is extremely doubtful, “particularly as nobody besides the Calomata, and that the collar-cells may, beså Poléjaeff has seen them in H. friabilis or any other performing other functions, also secrete the urine sponge." But is this so? for in another paragraph we However uncertain, he adds, this hypothesis may appen read :

“I think there can be no doubt that there is more prod "The spherical bodies which Schmidt and Poléjaeft bility in it than in the view, held by Carter and others consider as young stages of these filaments--in fact, as

the older authors, that the ciliated chambers are mere terminal knots, either dropped off, or on the way to pro- digestive apparatus." This seems a rather dreamy by duce a filament--have also been observed and carefully thesis, with no facts for its foundation ; but it is but it studied by Schulze, who

considers them as monocellular to remark that it comes at the very end of a volume what Algæ, which have nothing whatever to do with the is a record of numerous and important observations filaments."

Under the headings variability, parasitism, and sy Lendenfeld says that “no trace of filaments or ‘spores, biosis, many interesting details are given. The autta can be detected in the young embryos which are often thinks that certain forms of Aulena and Chalinops found in specimens of Hircinia.”

imitate "certain siliciferous Cornacuspongia. The On the physiology of the group, this monograph throws sponges have descended from those which they image but little light :

and, whilst they have lost the spicules in the fibres, the "Our knowledge of the vital functions of sponges is at have retained the outer appearance of their better present exceedingly unsatisfactory. We do not even tected ancestors in a most striking manner. Apparera know which parts of the sponge absorb nourishment, the primordial sponge ancestors were free-swimmi or, in fact, what kind of food the sponges take in. We and had no skeleton. Some produced a calcarese are equally ignorant concerning their respiration and others a siliceous skeleton; in both the subseque secretion."

development, the formation of ciliated chambers, There being then no facts to serve us as guides to the ancestors did not possess, and the fixing of the knowledge, the next “best thing” is to have recourse to and rays of the spicules, were the same. The primeed imaginations, and our author “thinks” that “it is by no Silicea had indifferent irregular spicules, from which

ixon and the tetraxon spicules were developed by an county, except in the extreme north and near the coast. aptation of the divergent development of the canal The mixed lands are found—one portion east of the heavy hem. The primordial forms of both lived in water lands between the Orwell and the Stour ; a second in the k in silica, and certain forms of both lost their spicules north, between Halesworth and Yarmouth; and a third consequence perhaps, of rising from deeper to shallower west of the heavy lands between Holston and Newite, where silica is more scarce. In both, some forms market. The sandy, or light, soils are in the extreme be lost the skeleton altogether, while others have re- north-west, in what is called the “Breck district,” between aced it gradually by spongin."

Thetford, and Mildenhall, where are found the rarest Whule acknowledging that some authors whose opinions plants of the county, such as Veronica hybrida, V. trimst carry great weight, such as Balfour, Bütschli, and phyllos, V. verna, and Apera interrupta. The coast is Kas, consider the sponges as a separate group, equal remarkable for the extent of its tidal estuaries and bays, value to the groups Protozoa and Metazoa, Lendenfeld creeks and havens. There are no cliffs of any consideranse but conclude that the sponges are, without doubt, able height, but a great extent of sand and shingle. The lesanoa, and certainly Coelentera, in the sense of being beach at Orford, where grows the great mass of Lathyrus raided with a simple body cavity.

maritimus, the seeds of which saved the life of many Toe last twenty pages of the work are devoted to a poor people in a famine in the middle of the sixteenth nopas of all the known sponges, giving the classes, century, is said to have the greatest breadth of sand anymilies, onders, and genera. In this extremely useful list where on the English coast. The rivers are shallow bere is a short analysis of the families and orders, streams with slow currents. In the north-east there are bich is based on the labours of Vosmaer, Ridley, Dendy, several lakes of brackish water, not so well known as the follas, schulze, added to those of the author's own. The Norfolk Broads, of which Braydon Water covers 1200, wthor ends his treatise with the statement that “Now and Thorpe Mere 1000, acres. The fresh-water lakes of har all the groups of sponges have been thoroughly in the county are few and small. There is a considerable estigated, we may consider our knowledge of their phylo- area of fen- and marsh-land, both in the north-west and metic afinities established on a satisfactory footing" east, so that we get in the county all the conditions that pyo!; but it seems well to call to mind the statement produce a rich low-country flora, and, superadded to the ith which he closes his short preface, and with which we common lowland plants, rarities characteristic of chalk ked the more inclined to agree, “our present knowledge country, the seashore, and fen-land ditches and marshes. f the group. ., has only just arrived at a stage corre The country is so easy of access from the centres where pending to the knowledge of the higher animals of half have lived many of the best botanists of bygone time, i centary ago" (p. 5).

such as London, Cambridge, Yarmouth, Norwich, and In concluding our only too brief notice of this important Saffron Walden, that the principal features of its botany park, for which all workers on the group must thank Dr. have long been known, and many excellent botanists, Lendenfeld, we may mention that the sponge portraits

from the time of Buddle down to the present day, have bere fur the most part photo-lithographs taken from the resided within its compass. The father of Suffolk botany arginal types; though in a few cases, where no good was Sir John Cullum, F.R.S., who lived near Bury St. pecimens were available, the lithographic illustrations Edmunds, and kept a diary between 1772 and 1785, in

which he has recorded the occurrence of upwards of 500 plants. To his son, Sir Thomas Cullum, F.R.S., who

was also an enthusiastic botanist, Sir J. E. Smith dediTHE FLORA OF SUFFOLK.

cated his “English Flora.” In the present work there is

not only a full general history of the progress of Suffolk Tas Flora of Suffolk. By W. M. Hind, LL.D., Rector botany, but, under each plant, the name of its first known ei Honington, assisted by the late Churchill Babing collector is registered. The first “ Flora" of the county wn, D.D., F.LS. With a Chapter on the Geology, was published in 1860. It was carried out mainly by the Citate, and Meteorology of Suffolk, by Wheelton exertions of the late Mr. E. Skepper, working under the Hund, M.D., F.R.C.S. Pp. 508, with a Map. (Lon- superintendence of Prof. Henslow. After it was pubdon Gilbert and Jackson, 1889.)

lished, Mr. Skepper made a great many notes for a new UFFOLK is a characteristic lowland maritime Eng edition, but he died in 1867. For several years the Rev.

lish county, the flora of which, at the present day, Churchill Babington, who settled in the county in 1866, botains absolutely no infusion of the boreal element. paid attention to the subject. In 1875, the Rev. W. M. 3 area is about 1300 square miles. The whole surface Hind, a very competent botanist, well known by his flat

, without any prominent rocks. It is underlain by “ Flora of Harrow,” settled in the county, and Dr. bulk

, which, in the north and west, lies immediately Babington sought and obtained his assistance to carry elow the subsoil

, but, in the south and east, is covered on the work. Dr. Babington died early in the present Tertiary and Glacial deposits, which at Harwich have year. ben found to reach a thickness of 1000 feet before the The bulk of the book is, of course, occupied by the halk reached. In White's history of the county, its enumeration of the species and an account of the dispils are classified into three groups: heavy lands, in tribution and special localities of the varieties. The Bach clay predominates ; mixed land, common mixed county is divided into five districts

, and the distribution kil

, ficha deep moulds, fen-lands, and rich marshes ; and of the plants is traced through them. Only the Phanerophs lands, consisting of sand over chalk. To the first gamia and Vascular Cryptogamia are dealt with, bu I belong the soils of the western two-thirds of the the mosses of the county have also been well worked.

re from drawings

There is also a detailed tabular comparison of the plants process, and finally of Thomas and Gilchrist's baže of Suffolk with those of Norfolk, Cambridgeshire, and process. Essex, and a short chapter on the characteristic plants of The chapter which deals with chemical principles and the different soils of the county, which will be found very changes, inserted for the benefit of those having a limited interesting to students of plant-dispersion. The chapters knowledge of chemistry, is valuable on account of the contributed by Dr. Wheeler Hind, the son of the editor, simple manner in which it is written ; this is particularis on the geology, physical geography, and meteorology of the case as regards oxidizing and reducing agents, de the county are very full, clear, and add greatly to the examples given of oxidation and reductior showing the interest of the book.

reactions very clearly. A chapter is devoted to the One of the most interesting circumstances in the county definition of metallurgical terms, refractory materials and flora is the occurrence of several maritime plants far fuel, another to the ores and alloys of iron, and then inland. In the Breck country, between Thetford and description of the various processes employed in the metziMildenhall, grow Vicia lutea, Erythraa littoralis, Rumex lurgy of iron and steel is given, attention being pretts; maritimus, Carex arenaria, Phleum arenarium, and equally divided between the two metals. Corynephorus canescens. These are all seaside plants, The most ancient and most difficult method of er and their occurrence fifty miles inland is accounted for tracting iron from the cre is what is known as the direct: by Prof. Newton and the editor by supposing that an arm method, and the author explains clearly the two causes of of the sea has penetrated here southward from the Wash its failure, whether in the case of the old Catalan or any, at a comparatively recent period.

of the modern processes, and the reason why the blast It is in Norfolk and Suffolk that the most valuable furnace, although an indirect, has proved so successfa! observations have been made, by Mr. Clement Reid and method. These two causes are "the easy oxidation his fellow-workers, in illustration of the time of origin iron by carbonic acid and water, at the temperature of our present British flora. The Cromer plant-bed ex- which ferrous oxide is reduced to the metallic state by tends into Suffolk, past Pakefield, to Southwold and Dun- carbon, carbonic oxide, or hydrogen, and the facility with wich. This is pre-glacial, and yet, out of upwards of forty which iron at a red heat combines with carbon." plants found in it that have been clearly identified, there The preparation of the ores for reduction in the blad are only two that are not British now-the spruce fir and furnace and their treatment therein are next brougat Trapa natans. At Hoxne, near Diss, lacustrine deposits forward, the advantages and disadvantages of the bot have been found resting on a bed of boulder clay, but blast, the utilization of waste gases, the dimensions and beneath beds which contain bones of the elephant. In form of blast furnace and subsidiary subjects being these are contained Salix polaris, S. Myrsinites, Betula treated of. nana, Hypnum sarmentosum, and a Pinus which is The metal being now in the state of pig-iron, the means probably sylvestris-all characteristic Arctic-Alpine types of refining and puddling are described ; the various ar associated with many lowland plants which grow un-rangements are set forth by which attempts have beer changed in Suffolk at the present time. A chapter in the , made to effect the work of the puddler by mechanicu book contains a list of all these plants, but their

geological means, whether by automatic rabbles or rotatory furnaces, position is not clearly explained.

and their relative advantages and disadvantages. A chap It will be seen that this is a very interesting and com- 'ter is devoted to the treatment of puddled iron unde: plete county flora, and that it is worthy of being studied the hammer and in the rolling mill, and to the tinnig: carefully by all who are interested in the distribution of and galvanizing of iron. our indigenous plants.

J. G. B. Leaving the subject of malleable iron, the author ner

considers the question of iron-founding. He describes THE MANUFACTURE OF IRON AND STEEL. various methods of moulding and casting, and the brands

the cupola furnace in which the pig metal is fused ; and the Iron and Steel Manufacture. By Arthur H. Hiorns. of pig-iron used for different purposes, are treated of. (London: Macmillan and Co., 1889.)

About a third of the book is devoted to the consideraTHIS *HIS volume is meant as a text-book for beginners, tion of steel ; it is in this branch of the treatment of ima

and will very worthily occupy that position. It is that the greatest development has occurred of late yeti. full of information, and information of the very kind and the book under review treats of all the modem which the student should possess before entering upon practice. It is pleasant to find, too, in the preparation of the study of the greater works of Percy or Fhillips. On an elementary work, that constructive perspective has the other hand, those already engaged in the metallurgy been employed. Modern processes are not brought into of iron and steel will find in these pages much that may prominence simply because they are modern, and anciene be referred to.

methods are not thrown into the shade is still employe The book begins with a brief history of the processes Amongst the latter we find full attention given to the that have been employed down to our own time, the land cementation process, and crucible steel; whilst a chapter marks in which are Dud Dudley's successful attempts to is devoted to each of the processes of Bessemer and smelt with coal at the beginning of the seventeenth cen Siemens. The book finishes with a chapter on steel tury; Cort's introduction of the puddling process in 1784 ; casting and on testing. Neilson's recommendation to use hot blast in 1828 ; the The volume before us is intended to assist pupils revolution produced in the iron trade by the invention preparing for the ordinary grade examinations of the Go of the Bessemer steel process in 1855, as supplemented and Guilds of London Institute, and its authore by R. F. Mushet, of the Siemens furnace and steel principal of the School of Metallurgy in connection with

he Birmingham and Midland Institute-is to be con volume he sums up the impressions produced upon him gratulated on the good work he has done in this con- by what he saw and heard in the course of his voyage. nection. The book is illustrated with 72 figures, which agree Mr. Moss, in dealing with matters which really interest with the simplicity and clearness of the diction, and ques- him, shows that he is an accurate observer and a man

His style, although plain and tions are found at the end of each chapter, which have unpretending, is well fitted for the task he has fulfilled. been well prepared to test the learner's apprehension of The best parts of the book are those in which he tries to its contents. We are pleased to be able to recommend convey some idea of the daily life led by those natives Uns Irtle work, as a foundation for the study of the whose customs he had an opportunity of studying. He metallurgy of iron and steel.

appreciates warmly some aspects of the various Polynesian types of character, but thinks that the people are likely to degenerate rapidly, unless they can be

provided with a better class of native teachers than most OUR BOOK SHELF.

of those to whom the duty of guiding them is now On the Creation and Physical Structure of the Earth.

intrusted. What is needed, he thinks, is, that the isBy J. T. Harrison, F.G.S., M.Inst.C.E. (London : freer scope for the imaginative powers with which they

landers shall have in their work and in their amusements Longmans, 1889.)

are endowed, and the exercise of which is too often This book brings to mind one of the most winning of the foolishly discouraged. Everything Mr. Moss has to say i Fagaries of childhood. A bright child of an inquiring on this subject deserves the serious consideration of those mimo will sometimes sit with comical sedateness listening to whom his warnings and counsels are either directly or to the talk of its elders. It may afterwards be overheard indirectly addressed. repeating to one of its playmates, or to some lucky adult who has the knack of winning its confidence, such letached scraps of the conversation as have found a resting place in its little brain; and, conscious even at its'

LETTERS TO THE EDITOR. early age of the necessity of some continuity in a narra- [The Editor does not hold himself responsible for opinions extrre, filling up the gaps with inventions or criticisms of its pressed by his correspondents. Neither can he undertake xwn, charming every way, but mainly on account of their to return, or to correspond with the writers of, rejected wter want of connection with the subject of the conver

manuscripts intended for this or any other part of NATURE, sation which it is attempting to report. So our author

No notice is taken of anonymous communications. ] has listened to the teaching of many geologists, and has ulled many detached passages from their writings : these

Who Discovered the Teeth in Ornithorhynchus ? be repeats to the world in a book, printing between them criticise my note which

appeared the week previous (November

IN NATURE of November 14 (p. 31), Profs. Flower and Latter and as little apposite as the child's prattle-hardly so 7, P. 11), concerning the discovery of teeth in the young Orni. amusing, however. The following passage is a fair sample Home discovered the teeth of the young Ornithorhynchus, by of the writer's own share in the book. The termination stating that the structures described and figured by Sir Everard of the Secondary Period, which introduced these altered are the well-known cornules of the adult animal. conditions of the surface of the northern hemisphere, was If they will take the trouble to turn to the plate cited by mereally the commencement of what is called the Glacial namely, Plate lix. of the second volume of Home's "Lectures,” epych in Europe. We have noted signs of glaciation 1814–and will read the accompanying explanation, they will see during the deposition of the upper chalk in India and that Home was familiar with the teeth of both the young and the North America, but now the conditions which induced that old

animal. glaciation are extended in such a manner as to unite

For the benefit of those who may not have access to Home's hese districts, and produce that enormous accumulation Lectures," I here reproduce outline tracings of two of his of snow and ice at the North Pole, the weight of which in figures. Plate lix. Fig

. 2, shows the teeth of the

young Ornithe Miocene epoch depressed the crust in that region there are two grinding teeth on each side.” The next figure is

thorhynchus—the "first set," as Home says, "to show that and upheaved the mighty mountain ranges to which I l a similar tracing from the succeeding plate in Home's " Lectures” have just referred."

(Plate Ix.), which represents, to again use Home's words, "the The book bristles with cataclysms and catastrophes. under jaw of the full-grown Ornithorhynchus paradoxus, to The shifting of a thin crust on an internal nucleus which show that there is only one grinder on each side.” Both of it does not fit, and incessant protrusions of granite, are these figures are natural size. invoked to account for phenomena which every-day In the face of these facts, further comment seems unnecessary, people still persist in thinking are satisfactorily explained I admit, of course, that Ilome did not discover the chemical by every-day causes. But the author is one born out composition of the teeth of the young animal—this was Poulton's of due time-two centuries too late. How he and Burnet

discovery.

C. HART MERRIAM. would have enjoyed a crack together! But there is this

Washington, D.C., November 30. to be said, the "Sacred Theory of the Earth” is Burnet's [We do not reproduce the outlines sent, as anyone interested Wt: the staple of the present work consists of extracts in the subject may see the originals, not only in Home's " Comfrom the works of others. The mottoes are verses from parative Anatomy," but in the Philosophical Transactions, where the first chapter of Genesis, but their relevancy to the they first appeared. -ED. Nature.] subject-matter of the chapters which they head is not

A. H. G. I SHOULD be very sorry to deny the credit of any discovery Through Atolls and Islands in the Great South Sea.

to Sir Everard Home, or anyone else, if any evidence could

be shown of its having been made. Of the figures cited by Dr. By F. J. Moss. (London : Sampson Low, 1889.) Hart Merriam, that of the younger animal seems (as far as can be s Mossma member of the House of Representatives

, judged from the roughly executed engraving, with the assistance New Zealand-started from Auckland, in September 1886, the hollows from which the true teeth have recently fallen ; that m the schooner Buster, for a voyage among the islands and islets of the outer lagoon world.” He was absent

of the old specimen, the same plates after they are fully grown,

and their surfaces worn down by attrition. This difference led seven months, and during that period he crossed the Home to conjecture that these plates were changed during the equator six times, and visited more than forty islands growih of the animal—a view which was corrected by Owen among the least frequented groups. In the present i Comp. Anat. of Vertebrates," vol. iii. p. 272), by the statement

obrious.

that each division or tubercle of the shorny) molar is separately therefore, a considerable probability that in the living anizal developed, and they become confluent in the course of growth.” the pigment is also soluble in water. I believe that this yelka By the way, no one can have been better acquainted with the pigment is undescribed, but I have not yet completed my stoche work of Home than his successor in the Hunterian Chair, Sir of it; in any case, it is not zoofulvin or picifalvin, or a Richard Owen ; and yet, in his numerous references to this "lipochrome."

FRANK E, BEDDARD subject (Art. “Monotremata," "Cyclop. Anat, and Physiology"; "Odontography"; "Comp. Anat. of Vertebrates," &c.),

Exact Thermometry. no trace is shown of any knowledge of a discovery which could not have failed to have interested him, if it had been made In the account which Prof. Mills has given (NATUKE, Deseos before his time.

ber 5, p. 100) of M. Guillaume's " Traité pratique de la There If a cursory perusal of Sir Everard Home's first account of métrie de précision," the permanent ascent of the zero-poiar el the mouth of the Ornithorhynchus (in the Philosophical Trans- a mercurial thermometer, after prolonged heating to a high to actions for 1800), or any interpretation placed upon his figures, perature, is stated to be due to compression of the bulb-rendered might lead anyone to infer, with Dr. Merriam, that the real more plastic by the high temperature-by the external atma teeth of the young animal had been discovered at that time, spheric pressure. the best possible authority may be conclusively cited against The constant slow rise of the zero-point of a thermometer u such an idea, no other than that of Home himself, who, in his the ordinary temperature is mentioned by Prof. Mills; and later description of the same specimen ("Lectures on Compara- | late Dr. Joule's observation of this change in a thermomet tive Anatomy," 1814), describes the organs in question as "the during twenty-seven years is specially alluded to. It may first set of cuticular tecth"-an expression quite incompatible with imagine, be taken for granted that after the lapse of a suffers their being the teeth described by Mr. Poulton and Mr. Oldfield length of time-possibly many centuries—a final state of eqer Thomas. It really seems superfluous to have to remind a brium would be attained ; and it has always appeared to zoologist of such high repute as Dr. Hart Merriam that the that the effect of heating the thermometer to a high temperature difference between teeth with the structure and mode of growth is simply to increase the rate at which this final state , which characterize these organs in the Mammalia generally, approached. It is my impression that, owing to the more rap** and the horny epithelial plates of Ornithorhynchus, is not merely cooling of the outer parts of the bulb after it has been blowe one of “chemical composition.”

W. H. FLOWER. the inner parts are in a state of tension, as, to a very exaggerate!

degree, in the Prince Rupert's drops; and that it is the gradua

equalization of the tension throughout the glass that causes the The Pigment of the Touraco and the Tree Porcupine. contraction ; in other words, that the process is one of the

annealing. ATTENTION has been lately again directed to the red pigment in the wing feathers of the touraco, which has been stated by that when a thermometer is exposed for a long time to a bo

This explanation appears to be supported by the facts--1 several observers to be soluble in pure water. Prof. Church, temperature, the zero-point rises rapidly at first, then mwen who was the first to experiment upon this pigment (The Student, more slowly, and finally becomes constant or nearly so ; (2) ta vol. i., 1868; Phil. Trans., 1869), quotes Mr. Tegetmeier and

the higher the temperature the more rapidly is this state a others, to the effect that this pigment can be washed out of the feathers by water. Later, M. Verreaux (Proc. Zool. Soc., 1871) evidence that the rate of ascent is influenced by changes

equilibrium attained. I do not know of any experime confirmed these statements from his own experiments while external pressure, and it seemed to be desirable to test the travelling in South Africa ; attempting to catch one of these birds

point. whose feathers were sodden with rain, he found that the colour stained his hands “blood-red.” A few years ago Prof. Kruken- and C, constructed by the same maker and of the same kind or

In order to do this I have exposed three thermometers, A, K berg (“Vergl. Phys. Studien ") took up the study of turacin-as glass, to a temperature of about 280° for several days in the same Prof. Church termed the pigment-and added some details of vapour-bath, under the following conditions:

The therm. importance to Prof. Church's account ; Krukenberg, however, contradicted certain of the statements quoted by Church with being suspended from above), and the tabes were heated by

meters were all placed in glass tubes closed at the bottom IC reference to the solubility of turacin in pure water, remarking vapour of boiling bromonaphthalene. One of the tulies-hu that the pigment in the dead bird is insoluble in water. A containing thermonieter C-was exhausted so as to reduce the writer in the Standard of October 17 is able "partially to con- external pressure on the bulb to zero; the others were open to firm" the assertion that turacin is soluble in pure water. Seeing the air. that there is some conflict of opinion with regard to this matter, mercury, but air was admitted into B and C to increase the

In thermometer A there was a vacuum over the I think it worth while to state that I found it quite easy to extract with tap water (warm) some of the pigment from a spirit, a resultant external pressure equal to the difference between the

internal pressure. Consequently, the bulb of A was exposed preserved specimen of the bird ; only a very

small amount could barometric pressure and that of the column of mercury in the be extracted in this way, and the feathers were not perceptibly stem of the thermometer; the internal and external pressures we decolorized even after remaining in the water for a fortnight. I the bulb of B were approximately equal; lastly, the interna also experimented upon a feather just shed from one of the speci; pressure on the bulb of*c was the sum of the pressures of the mens now in the Zoological Society's Gardens ; this was steeped column of mercury in the stem and of the air above it, while the in water for some time without any effect being visible, but after external pressure was zero. a period of two days the water became stained a very faint pink.

The following results were obtained :The touraco, however, is not a unique instance of a terrestrial animal with an external colouring matter soluble in water. Zero before heating ...

A Rise. B. Rise.

C Rose

. 0*15 O'10 am not aware whether other cases have been recorded, but I find a pigment of a similar kind in a South American tree porcupine After 2 hours' heating

0*35 0 25 (Sphingurus villosus).

... 0*50 0'35 0'30

So This porcupine has bright yellow spines which are for the

0*75 most part concealed by abundant long hair. The spines them. After an additional 54 hours selves are parti-coloured, the greater part being tinged with a

heating ...

1*30 I'10 vivid yellow; the tip is blackish-brown. I was unable to extract this pigment with chloroform, or with absolute alcohol even

Total rise of zero-point...

1'15 when heated ; like so many other colouring substances which are The thermometers were heated until 5 p.m, each day, an! insoluble in these fluids, the pigment could be extracted by the zero-points read on the following morning. potash or ammonia ; I found also that tap water, warm or cold, If the diminution of volume of the thermometer bull, usually dissolved out the yellow colour ; the action was slower than observed, were due to external pressure, the zero-point of when the water was first rendered alkaline by the addition of should have risen, that of B should have remained nestly ammonia, but, unlike the touraco, the pigment was nearly, if stationary, while that of C should

have fallen. Instead of als not quite, as completely dissolved. The skin, from which the however, the zero-points of all three thermometers rose at nearly spines were taken, was a dried skin of an animal recently living the same rate; therefore the yielding of the bulbs to presadie

, in the Zoological Society's Gardens ; it had not been preserved owing to the plasticity of the glass, if it occurred at all

, had in alcohol or treated in any way which might lead to the sup- sensible effect on the result.

SYDNEY YOC 3G position that the pigment was chemically altered. There is, University College, Bristol, December 12.

[ocr errors]

110

« PreviousContinue »