signal ingenuity, are deserving of great attention. They conceive the blood to consist essentially of serum, in which a quantity of red corpuscles is suspended; that each of these corpuscles consists of an external red vesicle, which encloses, in its centre, a colourless globule; that during the progress of coagulation, the vesicle bursts, and permits the central globule to escape; that, on losing their envelope, the central globules are attracted together; that they are disposed to arrange themselves in lines and fibres; that these fibres form a network, in the meshes of which they mechanically entangle a quantity of both the serum and the colouring matter; that these latter substances may be removed by draining, and by ablution in water; that, when this is done, there remains only pure fibrin; and that, consequently, fibrin consists of an aggregation of the central globules of the red corpuscles, while the general mass, that constitutes the crassamentum or clot, is composed of the entire particle. So far this seems satisfactory; but, we have seen, Dr. Hodgkin does not recognise the existence of external vesicle, or central nucleus; and he affirms, contrary to the notion of Sir Everard Home and others, that the particles are disposed to coalesce in their entire state. This is best seen when the blood is viewed between two slips of glass. Under such circumstances, the following appearances are distinctly perceptible. When human blood, or that of any other animal which has circular corpuscles, is examined in this manner, considerable agitation is, at first, seen to take place among the corpuscles; but, as this subsides, they apply themselves to each other by their broad surfaces, and form piles or rouleaux, sometimes of considerable length. These rouleaux often again combine, -the end of one being attached to the side of another, so as to produce, at times, very curious ramifications. (See Fig. 295, b.) The belief in the corpuscles being flattened disks is now generally admitted; but the form of the disk is found to be altered by various substances. Its external envelope readily admits the endosmose of fluids; so that, if placed in water, it may assume a truly globular shape. In examining the blood, consequently, it is advisable to dilute it with a fluid of as nearly as possible the same character as the serum. In the particles of the blood of the frog-as represented in Fig. 292-a nucleus is observed projecting somewhat from the central portion: this is rendered extremely distinct by the action of acetic acid, which dissolves the rest of the particle, and renders the nucleus more opaque. It then appears to consist of a granular substance. The vesicular character of the red corpuscles has been clearly shown by Dr. G. O. Rees,' by the readiness with which they become collapsed or distended by increasing or diminishing the specific gravity of the medium in which they float. In order to collapse the corpuscles, a solution of sp. gr. 1.060 is sufficient, but a solution of 1.070 or more is required to produce a decided effect. Solutions cease to distend the corpuscles when of sp. gr. 1.050 to 1·055, and to distend them well a solution of 1.015 or 1010 is desirable. He has, moreover, established, 'Ranking's Half-Yearly Abstract of the Medical Sciences, vol. i., Jan. to June, 1845, p. 250. that the red colouring matter of the corpuscle is seated, not in the envelope, but in the fluid within the vesicle, and that the envelopes themselves are white and colourless membranes. This is shown by increasing the specific gravity of the liquid in which the corpuscles float, the result of which is the escape by exosmose of the red coloured fluid from within the corpuscles; and, again, by applying water to the corpuscles, and inducing endosmose, the vesicles become distended and burst; their colouring matter mixes with the water, and the envelopes subside to the bottom of the vessel, forming a white layer. The red corpuscles of man have no nuclei, and their contents are probably homogeneous. They appear so at least when their surfaces are flat or slightly convex; but when concave the unequal refraction of transmitted light gives the appearance of a central spot, which is brighter or darker than the border according as it is viewed in or out of focus. (See Fig. 291.) Microscopical discordances are no less evidenced by the estimates, which have been made of the size of the red corpuscles; yet all are adduced on the faith of positive admeasurements. Leaving out of view the older, and, consequently, it might be presumed, less accurate observations, the following table shows their diameter in human blood, on the authority of some of the most eminent microscopic observers of modern times. Sir E. Home and Mr. Bauer, with colouringth part of an inch. matter, Eller, Sir E. Home and Mr. Bauer, without colour 1930 } 2000 2300 to 3500 ing matter, Müller, Mandl, Hodgkin, Lister, and Rudolphi, Sprengel, Cavallo, 3000 to 4000 The blood of different animals is found to differ greatly in the relative quantity of the red corpuscles it contains, the number seeming to bear a pretty exact ratio with the temperature of the animal. The higher the natural temperature, the greater the proportion of corpuscles; arterial always containing a much greater proportion than venous blood. In the greater part of the mammalia they have the same shape 1 Kirkes and Paget, Manual of Physiology, Amer. edit., p. 51, Philad., 184 . as those of man; but their size varies greatly in different families. It would appear, from the researches of Mandl,1 that of the mammalia the elephant has the largest, (th of a millimètre,) and the ruminantia the smallest; that the family of camels is the only one, whose corpuscles are not round like those of the other mammalia, but elliptical like those of birds, reptiles, and fishes.2 The chemical constitution of the blood corpuscles is not definitely settled. Two proximate principles have been discovered in themhematosin and globulin-hematoglobulin of Simon. The former, as mentioned hereafter, has been supposed to be the colouring matter. The latter, which differs from the globulin of Laennec, an impure hematosin mingled with some albumen,-is the main constituent of the globules, and is the same as the blood-casein of Simon. It has not been separated; but is presumed to differ but little in its properties from protein. It has been supposed that the red corpuscles are formed originally in the germinal membrane of the embryo; but, throughout the remainder of existence, in the blood from the chyle. Their origin is, however, by no means settled. Normally, they are not found outside the vessels; and are manifestly, therefore, not inservient to nutrition; but connected, in all probability, as shown elsewhere, with respiration and calorification. It is not determined whether they are capable of reproduction, or possess independent life. Dr. Carpenter3 thinks, that there can be no reasonable doubt, that they are to be regarded as nucleated cells, conformable in general character with the isolated cells that constitute the whole of the simplest plants; having each an independent life, and therefore the power of reproduction. Such too, is the view of Dr. Martin Barry and other microscopists. Wagner, Gulliver, and others, from observation of the blood of the batrachia, ascribe their origin to the colourless corpuscles to be mentioned presently, which, they consider, become red blood corpuscles when fully developed; whilst Dr. Carpenter strenuously maintains, that there is an entire functional as well as structural difference between the red and the colourless corpuscles of the blood of vertebrata. Observations by Dr. G. O. Rees' lead him to infer, that they multiply by division. On examining a portion of blood, kept at about its natural temperature, he observed the corpuscles assume an hour-glass form, which, increasing, eventually divided each corpuscle into two unequal-sized circular bodies. These, when treated with a strong saline solution, underwent the same exosmotic changes as are observed in common blood corpuscles. In addition to the red, white corpuscles are observed in the blood. These were noticed by Prof. Müller in that of frogs; and by M. Mandi 1 Manuel d'Anatomie Générale, p. 248, Paris, 1843. For numerous admeasurements of the red corpuscles of the blood of man and animals, see Note by Mr. Gulliver to Hewson's Works, Sydenham Society's edit., p. 237, Lond., 1846. 2 Op. citat., and Annales des Sciences Naturelles, 1824 and 1825. 3 Principles of Human Physiology, 2d edit., p. 499, London, 1844. 4 V. Bruns, Lehrbuch der Physiologie des Menschen, s. 140, Braunschweig, 1841. 5 Gulstonian Lecture; see Ranking, Half-Yearly Abstract, Jan. and July, 1845, Amer. edit., p. 251. 6 Gazette Médicale, 1837; and Manuel d'Anatomie Générale, p. 252, Paris, 1843. Fig. 293. in that of the mammalia. They are small, colourless corpuscles, finely granulated; insoluble in water, and strongly refracting light. According to Mandl, they may be separated into two species, some round, and containing two or three granules, which become more evident when they are treated with acetic acid: these are the true lymph corpuscles, described already (vol. i. p. 669); the others, generally also round; sometimes oblong; and at others irregular; the edges slightly notched; and the surface finely granulated. They appear to be composed of a multitude of small molecules, from 1000th to 1200th of a millimètre in diameter: some are also found single. These corpuscles are seen forming under the microscope, when blood, placed between two glasses, is attentively examined. They are, in Mandl's opinion, produced by the coagulation of fibrin, and hence are called by him fibrinous globules. More recently, however, he has abandoned this name, "because it rests on a chemical character, that requires confirmation; and because it is not drawn from anatomical characters, which ought chiefly to fix the attention of the microscopist." He now terms them white granulated corpuscles.1 These are the globulins of M. Donné, and are considered by him2 to be first elements of blood corpuscles. White Corpuscles of the Blood. In The white corpuscles are much less numerous than the red. health the proportion may be as 1 to 50; but in disease it is often as high as 1 to 10. Dr. Barry and Mr. Addison think, that the colourless corpuscles,— which have generally been regarded as lymph corpuscles, are formed from the central portion of the blood corpuscles: they consider them to hold an intermediate position between the true red corpuscles, and the greatly modified forms of corpuscles, which, in their view, are the basis of the tissues, as well as of pus and other globules. The most probable opinion, however, is that the white corpuscles of the blood are identical with the lymph and chyle corpuscles; and all, in the opinion of Dr. Carpenter,3 are connected with the elaboration of plastic fibrin, which must be constantly drawn off by the nutritive processes, and therefore require to be reproduced. His arguments on this head are certainly forcible. It was first observed by Wagner, that whilst the colourless corpuscles are met with in the nutritious fluids of all animals that possess a distinct circulation, red corpuscles are restricted to the vertebrata. The truth of this has been confirmed by Dr. Carpenter, who infers from it, that the function of the colourless corpuscles must be of a general character, and intimately connected with the nutritious properties of the circulating fluid; whilst that of the red corpuscles must be of a limited character, being only required in one division of the animal kingdom. One of the strongest arguments, however, in favour of the function of the white corpuscles mentioned above, is the connexion between the generation of white corpuscles in the blood, and the production of fibrin in the inflammatory process. This increase is 1 Manuel d'Anatomie Générale, p. 554, Paris, 1843. 2 Cours de Microscopie, p. 86, Paris, 1845. 3 Op. cit., 2d edit., p. 506, Lond., 1844. 4 Op. cit. evidently the result of the local inflammation, and is observed to commence before the occurrence of any constitutional phenomena. The microscopic observations of Messrs. Addison,' Williams, Gulliver, and others, have established, that a great accumulation of white corpuscles takes place in the vessels of an inflamed part, partly owing to an attraction of the corpuscles towards the seat of inflammation, and partly, they were satisfied, by an actual reproduction of fresh corpuscles, which must have been owing either to their own power of generating themselves, or to some change in the blastema or fluid of circulation in the part, which favoured a more abundant production. Dr. Carpenter is a believer in the first mode of production; and certainly his view, that the production of fibrin in the blood is closely connected with the developement of white corpuscles, has strong arguments in its favour. Messrs. Kirkes and Paget' are strong believers in the development of the human lymph or chyle corpuscle into the red corpuscle, a belief which is not necessarily inconsistent with that which ascribes to them the production of fibrin; and the view is confirmed by the phenomena recorded by different observers. Mr. Lane, for example, found the ruddy colour of the horse's chyle due to the presence of Fig. 294. B red corpuscles; and he and Mr. Ancell observed imperfect blood corpuscles in the large lymphatics, and ascribed the rose-colour of the lymph to them. The thoracic duct of the horse, according to M. Gulliver, often appears as a coloured tube from the number of these corpuscles in the chyle, which he generally found to be smaller, more irregular and less perfect ▲. A lymph or white blood-corpuscle. B. The same, in pro- in shape than the red D E F Developement of Human Lymph and Chyle Corpuscles into Red Corpuscles of Blood. cess of conversion into a red corpuscle. c. A lymph corpus cle, with the cell-wall raised up round it by the action of water. D. A lymph corpuscle, from which the granules have almost all disappeared. E. A lymph corpuscle, acquiring colour; a single granule, like a nucleus, remains. F. Ä red corpuscle, fully developed. corpuscles in the blood. Schultz and Gurlt' also noticed the chyle of a reddish colour from the presence of blood corpuscles, of which they suppose, with Simon of Berlin," the formation to begin in the chyle; and M. Gulliver adds, that the transition of the corpuscles of the chyle or lymph into the red corpuscles of the blood, seems now to be commonly admitted in Germany; and, long ago, Mr. Hewson' thought "it could not be denied," that the office of 1 Med. Gazette, Dec., 1840; Jan. and March, 1841. 2 Principles of Medicine, Amer. edit., by Dr. Clymer, pp. 214, 215, Philad., 1844. 3 Manual of Physiology, Amer. edit., p. 67, Philad., 1849. 4 Appendix to English edition of Gerber's Anatomy, p. 93, and Hewson' Works, Sydenham Society's edit., p. 276, Lond., 1846. 5 Müller, Elements of Physiology, by Baly, i. 563, Lond., 1838. • Animal Chemistry, Sydenham Society's edit., i. 121, Lond., 1845; or Amer. edit., Philad., 7 Works, Sydenham Society's edit., p. 286, Lond., 1846. 1846. |