A

ed, with great care, into the ground. At the same time, eighteen precisely similar wheat plants, grown from the same seed, were placed in the ground in a pot, and covered by a bell glass, to be kept as check plants. The Ecidium was obtained from North Wooton, distanced three and a half miles, and the spores were used for inoculation within two hours from the time they were gathered. number of them were at the same time placed upon a drop of water on a glass slide, and kept in a damp atmosphere, for forty-eight hours, when they were found to have germinated freely, which was proof positive of their vitality, and‍ that they had not been injured by removal. Both groups of plants were watered from time to time, which was done by raising the edge of the bell glass covering them, an inch or two. At the end of ten days the bell glasses were removed, and the plants examined daily. On the twenty-fifth day a single spot of Uredo was observed upon one of the infected plants; the others all remaining free. On the thirtieth day this leaf was removed and examined, and found to be veritable Uredo linearis. On the thirty-second day two more of the infected plants had Uredo upon them, but it was now found upon the check plants: that is, in twenty-two days from the time they were uncovered. On the fortythird day the experiment was concluded, when the whole seven of the infected plants had Uredo upon them, as well as sixteen out of the eighteen check plants.

The result of these thirteen experiments may be thus summarized:

Seventy-eight wheat plants were infected with the spores of Acidium berberidis and ninety-eight similar wheat plants kept as check plants against them. Of the infected plants seventy-six per cent. developed Uredo in an average of 24.4 days. While in the same period seventy per cent. of the uninfected plants became spontaneously attacked by Uredo.

Our Histological and Pathological Laboratories.

II.

In my previous article, published in the December number of this JOURNAL, I attempted a fair exposition and criticism of the outfits and manner of conducting the laboratories in connection with medical schools. My failing to clearly state my opinion as to what should constitute a good working laboratory, has caused numerous inquiries. In order to answer these and to bring the matter for discussion, I herein give my views on the subject.

First of all the room chosen should be so situated as to eliminate any possibility of tremor from outside causes, and so constructed as to be but slightly susceptible to motions within. This is all-essential. That it should be well lighted on all sides, is a convenience but not a necessity. What it lacks in natural light we can supply, and artificial light is to be preferred, owing to its steadiness. The floor should be oiled thoroughly and kept free from carpets or other covering. The walls should be smooth and of a dark color, thus preventing any chance of cross rays by reflection. Dark closet for storage, and chemicals injured by light; shelving for stock-bottles and material in hardening fluids; sink with hot and cold water; several aquaria for frogs, salamanders, etc., are all needed.

A cabinet containing various highpower lenses, binocular eye-piece, freezing microtomes and other apparatus, occasionally needed for demonstration or inspection, is an important addition.

Each student must be provided with a table, the particular style of which is a matter of taste. I much prefer Queen's revolving table, to which has been added numerous little drawers in which to keep cleaned covers, slips, brushes, knives, needles, and any small apparatus not in use. On each table should be a micro

scope with triple nose-piece and three or more lenses, of powers as follows: 11⁄2" or 1", 2/3" or 12", 4" or "; 2′′ and "Huyghenian eye-pieces, and 1⁄2" or 14" solid ocular, all of which should drop easily into their places. This is a point that microscopists should insist upon-then, and only then, will the makers learn wisdom. The microscope should have rack motion, and the fine adjustment adjustment should be behind, if for no other reason than convenience; the stage not more than 4" thick, including carrier or mechannical stage, and certainly not less, as it cannot thus be made, and at the same time be steady. It must have a stop for the Maltwood finder. The mirror should swing above the stage, the diaphragm of the iris pattern, or so constructed as to work close to the slide. The swinging substage I would not insist upon, though at times it may be a convenience, it is not a sine quâ non as some would have us believe.

In addition, a camera lucida that can be used in all positions of the microscope is a necessity. Don't forget a polariscope in the outfit. This is indispensable; hence a stand having a shifting, polarizing apparatus, as the "lithological" stands, would, in some respects, be the best stand for our work. A bull's-eye condenser, eye-piece and stage micrometers, section cutters, knife and carriers, a lamp with an Argand burner are all necessary articles.

For dissection and tearing, a dissecting microscope, scissors, needles, knives, brushes, etc., must be provided each student, as well as turn-table, nest of porcelain saucers (not less than eight in a nest), mounting media, finishing cements, staining fluids, alcohol, etc., and capped bottles to contain them, these with small spiritlamp, bell and watch-glasses, will complete an outfit.

A set of reagents for urinary analysis, acids, test-tubes, beakers, washbottles, water and sand-baths, large spirit lamp, drying oven, Bunsen bur

ner, imbedding material, etc., should occupy the centre of the room on the chemical table.

A cabinet supplied with normal and pathological slides is a great help to students, as well as all the important current and standard literature bearing on the subject.

The course of instruction should begin with a thorough elucidation of the mechanical and optical principles involved in the manufacture of the microscope. I clip the following from the Journal of the Royal Microscopical Society for December, as bearing directly on this point: "Microscopists have for many years insisted that it is absolutely essential that histologists should be grounded in the theoretical principles applicable to the instrument with which they work, and that if this is not done, not only will erroneous interpretations of structure be put forward, but many points of importance will be altogether missed.

In England (and America, too) this view has not been accepted in practice; and an histologist who attempted to determine the true structure of an object by experimental or theoretical optical considerations was a rarissima avis, indeed."

It would be well to acquaint the student next with the manipulation of his lenses, and the ascertaining of their powers. Follow this with instruction (practical of course) on the use of immersion or collar-adjustment lenses and eye-piecing.

A thorough study of the normal fluids of the body and the simple tissues should immediately be followed by the study of the same in diseased conditions. This method I prefer to that of postponing pathological histology until the entire course of normal histology has been gone over. The student thus saves much time and learns more rapidly the distinctive differences in the appearance of the tissues, after the simple tissues the membranes and organs are each considered in the way above stated. I hope this paper will excite com

ment by educators, and thus bring before us a subject on which we have been painfully silent, much to the injury of our students.

J. W. CRUMBAUGH.

PHILADELPHIA.

EDITORIAL.

PERSONAL.-We thought that Dr. J. Pelletan, editor of the Journal de Micrographie, had stopped the publication of his periodical. But the October number (1881) has been given to us by a friendly hand, particularly on account of an article concerning ourselves, which, although not such as would ordinarily be considered complimentary, is at least a rather outspoken critique, and more or less instructive for that reason. The nature of the article will be understood when we add that it is principally a translation from The Microscope, published by Prof. Stowell.

Now, if Dr. Pelletan does not treat us with more kind consideration in the future, we shall feel in duty bound to say some harder things about his peculiar transactions than we have ever said about anybody yet -and some of our readers will admit that such a criticism would be rather

severe.

THE NORTHERN MICROSCOPIST. We have received from the publisher some copies of The Northern Microscopist (London) for distribution among the microscopists of America, as advertised in another place. It is an illustrated monthly magazine which completed its first volume in December, 1881. We can commend it as an ably conducted journal, and would be pleased to have it widely circulated in this country.

CORRESPONDENCE.

A MUCH Needed Stop.

To the Editor:-For some months past I have been intending to offer, through this JOURNAL, a suggestion to our mak

ers of microscope stands, and it is this: that they attach a thumb-screw in such a way that when the instrument is focussed on the object it can be securely set to that position.

While adding materially to the value of the microscope, particularly for soirée and exhibition purposes, it need not increase its expense beyond the merest trifle.

For public occasions the stop might be so arranged that the screw could be readily removed by the owner, and thus all tampering with the adjustment and consequent ruining of valuable slides prevented," a consummation devoutly to be wished," and which no notice of "hands

off" and "please do not disturb the instrument" has hitherto accomplished.

Who will be the first to utilize this suggestion, and thus deserve the thanks of all microscopists?

J. T. BROWNell.
MANSFIELD, Pa., Jan. 21, 1882.

NOTES.

-It is with no little satisfaction that we notice the publication of Bulletin No. 1 of the American Museum of Natural History of this city. It is the intention of the officers of the Museum to publish in this form, from time to time, the results of investigations conducted at the Museum, Bulletin No. 1 contains three articles by Prof. R. P. Whitfield, illustrated by wood-cuts and by four excellent lithograph-plates. It is in all respects a publication creditable to the Museum and to all concerned in its preparation.

-Messrs. Bausch & Lomb have devised a new immersion-condenser, which it is expected will soon be ready for sale. We have seen one of them, but have had no opportunity to give it a practical test. It seems to be ingeniously devised, and will doubtless prove very useful.

-Mr. A. A. Julien has published an article on "The Examination of Carbon Dioxide in the Fluid Cavities of Topaz," in which some interesting information regarding the nature of such inclusions, and the best methods of studying them is given. The article is published in pamphlet form, illustrated by four cuts.

-Prof. Bessey, in a late number of the Botanical Gazette, recommends the asparagus for histological study in the botanical laboratories. The stem of this plant is a good type of monocotyledons,

while for dicotyledons the pumpkin is a good representative,

-The eleventh edition of Messrs. R. & J. Beck's Illustrated Catalogue of optical instruments is a pamphlet of 176 pages, containing illustrations of the microscopes and accessory apparatus manufactured by that firm. It is a useful pamphlet for reference, and every microscopist should be willing to send 15 cents for a copy.

-Messrs. J. W. Queen & Co. have also recently issued the forty-ninth edition of their illustrated catalogue of optical instruments, which is likewise a book of reference, containing more than 180 pages.

-Dr. George M. Sternberg is now engaged in writing a book on practical microscopical work, which is intended to give a general knowledge of such subjects as are seldom treated in a satisfactory manner in our popular text-books. The work will be ready before long and we will take occasion to refer to it again as soon as the plan is more definitely announced. It will be illustrated by heliotype plates.

MICROSCOPICAL SOCIETIES.

The fourth annual reception of the New York Microscopical Society was held at Chickering Hall on the evening of the 3d of February. It was the most successful of all the public exhibitions given by the Society, and it was attended by about five hundred persons. The audience was highly appreciative, and included some of the most cultivated persons in New York society. The retiring President, Mr. R. Hitchcock, delivered the annual address, which is printed in full in this JOURNAL. After the address an exhibition of objects was given which, if not one of the largest, was certainly one of the best and most interesting of any that has been given in this city.

The exhibitions of the Society are given exclusively by members, with instruments belonging to them or to the Society. No member is allowed to show more than three microscopes, and the sole object of the exhibition is to combine instruction with entertainment. Among the objects exhibited, the following are worthy of especial mention: Circulation of blood in a frog rendered motionless by curara, by Mr. J. L. Wall. Circulation in the yolksac of a young trout and of a young salmon, both of which were provided by Mr. E. G. Blackford, and shown by the use of

Holman's syphon slides. Mr. F. Collingwood showed the blood flowing in the tail of a fish; Mr. W. H. Mead showed cyclosis in Anacharis and Mr. Hitchcock the same in Nitella. Mr. F. W. Devoe showed a spider's nest with its pure-white eggs, a very beautiful object, and also the eyes of a living spider. Mr. E. C. Bogert showed some very beautiful insect eggs on a maple leaf. Several members exhibited different forms of living infusoria, rotifers, stentors, vorticella, etc., which they are now able to procure from Mr. Balen. Heretofore, there has been some difficulty about obtaining living infusoria in the city, when wanted for such occasions, but Mr. Balen has now removed it.

We have only mentioned some of the most interesting objects-the list included thirty-three different specimens.

The Society is in a prosperous condition, and we trust it may have a successful future under the direction of the new Board of Managers. Mr. Benjamin Braman is the President and Mr. C. S. Shultz Corresponding Secretary. The address of the Society is 64 Madison Avenue.