1847] Influence of System on Coagulation. 9 by an observation of Dr. Hunter to the effect, that the faintness which comes on after hæmorrhage, instead of alarming the byestanders, and inducing them to support the patient by stimuli and cordials, should be looked upon as salutary, as it seems to be the method Nature takes to give the blood time to coagulate" Suspecting that the disposition to coagulate was increased in those cases where the vital powers were weakened, the author performed the following conclusive experiment :-" Believing it would be sufficient for this purpose to attend to the properties of the blood, as it flows at different times from an animal that is bleeding to death, I therefore went to the markets, and attended the killing of sheep; and having received the blood into cups, I found my notion verified. For I observed, that the blood which came from the vessels immediately on withdrawing the knife was about two minutes in beginning to coagulate; and that the blood taken later, or as the animal became weaker, coagulated in less and less time; till at last, when the animal became very weak, the blood, though quite fluid as it came from the vessels, yet had hardly been received into the cup before it congealed. I have also repeated the experiment, by receiving blood into different cups at different times, whilst the animal was bleeding to death; and though the time taken up in killing the animal was not commonly more than two minutes, yet I observed, on comparing the cups, that the blood which issued last coagulated first." L. c., p. 46. The truth of this conclusion, shaken for a time by the experiments of the late Mr. Hey, was fully established by the valuable researches of Mr. Thackrah; and must ever be regarded, in respect to the means of suppressing hæmorrhage, as one of the most fundamental principles connected with the blood. Although so much has been since written on this subject, the admirable observations of Hewson leave little to be desired. "As hæmorrhages," he says, seem to be stopped, partly by a contraction of the bleeding orifices, and partly by the coagulation of the blood, and as the disposition of the blood to coagulate is increased by weakening the body, and likewise the contraction of the bleeding orifices is promoted by the same means, it is therefore evident that the medicines to be used should be such as cool the body, and lessen the force of the circulation; and experience teaches us, that such are the most efficacious. It likewise shows that all agitation of mind and all bodily motion should as much as possible be prevented; because they increase the force of the circulation, and are thence unfavourable to the stopping of the hæmorrhage. But that languor and faintness being favourable to the coagulation of the blood, and to the contraction of the bleeding orifices, should not be counteracted by stimulating medicines, but on the contrary, should be encouraged. And as evacuations weaken the body more when they are sudden, we see a reason why blood-letting should be advisable in hæmorrhages, and why a large orifice should be preferable to a small one, when we want to produce that languor or faintness, or that weak action of the vessels, so useful for the stopping of the hæmorrhage." P. 77. There is an interesting point connected with the coagulation of the blood; namely, that the process is retarded or entirely prevented, so long as the blood is in contact with the living tissues; not merely with the blood-vessels, as where Hewson tied up the jugular vein of a dog and found but a very slight coagulum at the end of two hours and a quarter; but even occasionally in cases of extravasation. Thus, Mr. Gulliver mentions the case of a soldier, who had received a contusion in his loins, and in which five ounces of blood, evidently effused at the time of the accident, was let out twenty-eight days afterwards and found to be as liquid as if just drawn from a vein, though it coagulated in a cup in less than thirty minutes. The experience of most observers and practitioners must have furnished similar instances. The authority of Mr. Hunter is so influential in all points relating to the blood, that it is particularly necessary to correct any errors into which he may have fallen; we therefore would call the attention of our readers to the following observations of Mr. Gulliver, relative to a point of some physiological interest. "The causes usually given, on the authority of Mr. Hunter, as altogether destroying the coagulable property of blood and the contractility of muscle, are some of them so doubtful that they all require to be examined anew. Thus, in a man killed by lightning, Dr. Davy observed some soft coagulum in the heart, and that the fingers were rigid, although the examination was not made until the body was rather advanced in putrefaction. Sir Charles Scudamore invariably found the blood coagulated as usual in animals killed by electricity. Sir B. Brodie found that the irritability of the muscular fibre was not destroyed in a guinea-pig which had been instantly killed by an electric shock. "Dr. Andrew Smith commonly saw coaglated blood in the hearts of antelopes run down by dogs. In a hunted hare Dr. Davy saw, he informs me, some coagulated blood. So did I in one that had been run for thirty-five minutes and then killed by the Windsor harriers. Finally, as to a blow on the stomach: In a cat killed by a kick, which ruptured the stomach and liver, I found coagulated blood in the heart, and the limbs rigid, seventeen hours after death." P. 21. We proceed to notice that constituent of the blood, which, since the invention of the microscope, has ever been a favourite branch of research, and to which a large part of Hewson's writings is devoted; we allude to the coloring matter, composed of the red corpuscles. Discovered originally by Malpighi, and affirmed erroneously by Leeuwenhoek, to be globular, the red corpuscles were first demonstrated to be flattened discs by Hewson. The method by which he ascertained this fact evinces his usual tact and discrimination: being convinced that former observers had failed to detect the true figure of these bodies in consequence of their being so much crowded together, that the blood, when viewed through the microscope, appears a confused mass, it occurred to him to dilute it with serum, in which the discs remain unaltered. In making this observation, it is necessary, as Mr. Gulliver points out, to examine the corpuscles in their own serum; for so subtle are the influences operating on them, that it may be difficult to distinguish correctly their outline in the serum of another animal, which is apt to cause them to aggregate into clumps, as when the serum of the horse is added to the blood of other mammals, and, in consequence, as it would seem, of some difference as to the amount of saline matter. It is well known that whilst in mammalia and man the red corpuscles are circular and biconcave, in the oviparous vertebrata, they are elliptical and bi-convex; there are, however, some remarkable exceptions to this general principle, for in the camelidæ among mammals the corpuscles are oval, whilst in cyclostomatous fishes and amphioxus, the discs are circular; 18471 Formation of Red Corpuscles. 11 but in both of these instances there is no deviation as to structure, the oval corpuscles of the camel, for example, agreeing with those of other mammalia in having no nucleus (Gulliver), whilst those of the lamprey have that characteristic of the oviparous vertebrata (Wharton Jones). The question relating to the organization of the red discs, for that they are organized bodies has long been known in a general way, and has been specially demonstrated in late years, requires that we should refer to the first formation or development of the corpuscles; a subject minutely examined by Hewson, and which has subsequently received much attention, especially in the elaborate memoirs of Mr. Wharton Jones, lately published in the Philosophical Transactions, entitled "The Blood-corpuscle in its different phases of Development in the Animal Series." The fully-formed red corpuscle consists, according to the best observers, of a colourless envelope or vesicle, and of coloured contents; in the oviparous vertebrata, but not in mammals or man, there is a nucleus, which is insoluble in water or acetic acid. Hewson, it is well known, confidently contended for the existence of a nucleus in mammalia; this opinion is strongly expressed in the following passage:-"From the greater thickness of the vesicles in the human subject, and from their being less transparent when made spherical by the addition of water, and likewise from their being so much smaller than those of fish or frogs, it is more difficult to get a sight of the middle particle, rolling from side to side in the vesicle, which is become round; but with a strong light, and a deep magnifier, I have distinctly seen it in the human subject, as well as in the frog, toad, and skate.”—(P. 224). He further affirmed that the nucleus is white, and the vesicle red. Although, as we have stated above, the nucleus is apparently wanting in mammalia, yet it was necessary to state Hewson's opinion, because it is intimately connected with the celebrated theory he so strenuously advocated respecting the formation of the red particle. This theory briefly stated is, that the red corpuscles are formed by the lymphatic system and its appendages, consisting, according to the author, of " the lymphatic vessels, lymphatic glands, the thymus, and the spleen :" of these organs, the lymphatic glands and the thymus, so long as it persists, form the white nuclei or "central particles," as Hewson terms them, whilst the lymphatic vessels and the spleen form the red vesicles.* No one who has not carefully considered the important body of evidence adduced by Hewson in support of his doctrine, or who is unacquainted with the minute anatomy of the present day, is qualified to pronounce an opinion upon its value; and no one, we may confidently affirm, who has thus studied his profound researches, whatever may be the conclusion at which he may arrive as to the particular fact of the formation of the red corpuscle, can rise from their perusal without feelings of admiration for their author, and of surprize that he should on so many points have closely approached some of the deepest truths of structural anatomy. Our limits will, however, only allow us to make a few extracts. Hewson proved that the lymphatic Hewson erroneously supposed that the seat of colour was in the envelope of the red corpuscles, and this mistake has been repeated by some writers of the present day. glands are secreting organs, and, in the following paragraph, has indicated their true structure, lately more precisely demonstrated by one of the most successful observers of the present day, Mr. Goodsir. "The arteries and veins are principally spread on the coats of the lymphatic vessels, so that we here find the requisites to form a lymphatic gland; for as we prove that many of the lymphatic glands in the human body are no more than a congeries of arteries, veins, nerves, and lymphatic vessels convoluted, it is probable that all lymphatic glands may be formed in the same manner; so, perhaps, it may be the same thing in nature, or the same purposes of the animal economy may be equally well answered, whether the parts composing a gland (viz. arteries, veins, nerves, and lymphatic vessels) be circumscribed in a proper membrane, or spread over a large surface. This, perhaps, will be more fully proved by some experiments and observations which I shall hereafter publish on the minute structure of glands." L. c. p. 251. It is Mr. Falconar, the editor of Hewson's posthumous works, who is here speaking for his friend; unhappily he did not live to fulfil this promise, having died very shortly afterwards. The peculiar secretion of the lymphatic glands, consisting of the now well-known lymph-corpuscles, is thus described: "On cutting into a fresh lymphatic gland we find it contains a thickish, white, milky fluid. Then if we carefully wipe or wash this fluid from any part of the cut surface, and examine it attentively in the microscope, we observe an almost infinite number of small cells, not such as have been before described, or that have been supposed to exist in the lymphatic glands, but others too sinall to become visible to the naked eye." P. 251. They are further on spoken of as "small, white, solid particles ;" and the lymphatic vessels are said to be analogous to the excretory ducts of other glands, the proof being that, if a ligature be made on the lymphatic vessel coming from a gland, a fluid is found of the same kind as that contained in the gland itself. But other and more direct indications are adduced thus, it is repeatedly asserted that red corpuscles were seen in the fluid taken from the lymphatic vessels after they had passed through the glands; that when a ligature had been applied around the vessels of the spleen, in an ox first killed, "the lymphatic vessels soon became turgid, and were distinctly seen filled with a red fluid," and on diluting some of this fluid with a weak solution of Glauber's salts, exactly the same appearances were exhibited as those seen on similarly examining the blood. (P. 272.) An important fact corroborative of Hewson's theory, may be here adduced; it is that the chyle unquestionably acquires its peculiar corpuscles as it traverses the mesenteric absorbent vessels and especially the glands; so that either these lacteal vessels and glands must be the formative organs of the chyle-corpuscles, which are on the average somewhat smaller than the red discs (their diameter being about of an inch); or these corpuscles must be the result of certain molecular changes accomplished by the chyle itself. Although the experiments which are affirmed to prove the existence of red corpuscles in the lymphatics, are not free from objection; and may in part be explained by the circumstance first noticed by Mr. Lane, that in opening the absorbents, some small blood-vessels are wounded and so allow their red discs to become mixed with the lymph; still the fact contended for by Hewson, has been confirmed by too many accurate observers to be 1847] Formation of Red Corpuscles. 13 any longer a matter of doubt. The principal evidence hitherto obtained on this point is thus summed up in Mr. Gulliver's notes. "Red corpuscles are certainly sometimes found in the lymphatic vessels, and generally in those of the spleen of the horse and ox; but it would appear that the reddish colour of the splenic lymph is not constant. Mr. Lane found the ruddy colour of the horse's chyle due to the presence of red corpuscles; and he and Mr. Ancell observed imperfect blood-corpuscles, and attributed the rosecolour of the lymph to them, in the large lymphatic vessels. The thoracic duct of the horse often appears as a coloured tube from the number of these corpuscles in the chyle, which, as described in the Appendix to the English edition of Gerber's Anatomy,' p. 93, I have generally found to be smaller, more irregular and less perfect in shape, than the red corpuscles in the blood; and the same observation is applicable to the red corpuscles in the splenic lymph of this animal. Dr. Simon's observations on red corpuscles in the thoracic duct of the rabbit and horse, are to the same effect. Schultz and Gurlt also noticed the chyle of a reddish colour from the presence of blood-corpuscles, of which they suppose, with Simon, the formation to begin in the chyle. The transition of the corpuscle of the chyle or lymph into the red corpuscle of the blood seems now to be commonly admitted in Germany. Dr. Davy informs me that he found a small portion of red crassamentum in the thoracic duct of a man who died suddenly of apoplexy." Note CXLI., p. 276. Hewson's theory, as he himself readily perceived, is open to the objection that the spleen may be removed in a living animal without preventing the formation of the red particles. His answer is, that this organ is not the only one provided for the formation of the vesicular portion, the lymphatic vessels being endowed with the same power;-" Nature has given the spleen as an auxiliary to the lymphatic system, in order to the more commodiously, expeditiously, and completely forming the red part of the blood." In the same way with respect to the thymus, which exists only in the early period of life, although its agency is at that active time required" for the purpose of forming more of the central particles of the blood than could have been made by the lymphatic glands alone," yet subsequently when the demand is less, the thymus can be dispensed with, the absorbent glands being then competent to supply the central nuclei. Mr. Gulliver justly observes, in reference to this latter subject, that Hewson's observation to the effect" that the lymphatic vessels of the thymus do carry a fluid, however it may get into them, like that of the thymus, and pervaded by the same globules," has never been refuted; and he quotes the authority of Sir A. Cooper, that the lymphatic vessels are the absorbent ducts of the gland, and the carriers of its fluid into the veins of the lower part of the neck. It will not be superfluous to remark in this place, that this, the most profound and important of all Hewson's researches, could not be properly appreciated at the time when it was announced: it must be viewed in connexion with the cell-theory, with which the formation of the "central particles" (nuclei) and of the enveloping" vesicles" (cells) has a clear and distinct relation. The minute and elaborate microscopic observations of Mr. Wharton Jones, which immediately bear upon the question we are considering, are worthy of the most careful attention. The object of these memoirs is to prove that the red corpuscle passes through several successive stages in its deve |