The changes of the blood globules in the spleen are not exactly similar in all circum stances, either as regards the quantity of the cells thus changed, or the degree of metamor phosis which they undergo. In fishes, all the blood globules, without exception, may be recognised as decomposing; yet the quantity of these varies, i. e. the number and size of the vesicles and masses previously described varies in a considerable degree in different in dividuals and species, although no very de finite laws have as yet been found out. Reptilia exhibited the following peculiarity. In newly-caught individuals, the cells con taining blood corpuscles were very numerous and distinct ; but in those which had fasted one, two, or three days, they occurred in exceedingly small quantity ; while, finally, by a longer duration of the fasting (a week or more), they exhibited themselves in very great number, and of extraordinary distinct ness ; while at the same tinie the spleen became large, dark red, and very rich in the normal blood corpuscles. When newts which had fasted a week were fed, the cells previ ously existing, and the unchanged blood cor puscles, vanished, since they were changed into colored granule-cells, and only on the sixth day after the feeding did such cells re appear ; but in three days afterwards ahnost all of these had again experienced a meta morphosis into granule-cells. In nzannnalia I have, in a series of cases, seen the decom. positions of the blood corpuscles in as little as five, six, and more hours after eating, while immediately after the reception of food, or after a day's fasting, I have failed to observe it. At my advice, Landis§ instituted experi ments concerning this on thirty rabbits, and obtained the following results. Of fifteen animals which were examined, two, five, and eight hours after eating, cells with unchanged blood globules were found in eleven ; in five they were in masses ; in six separate ; in four cases they- did not occur at all. Fifteen other animals, which were killed twelve, twenty-four, and forty-eight hours after eating, showed in eleven cases no trace of the cells mentioned ; in two cases many vvere present, in two cases a few only. And, vice versa', golden yellow granule-cells (metamorphoses of the cells with unchanged blood globules) occurred fourteen times in the latter animals; ten times in great quantity, once in consider able numbers, and thre-e times very sparingly, while in one instance only were they alto gether wanting. In the fifteen animals first mentioned these were twice absent, five times sparingly present, twice in considerable num bers, and six times in large quantity. The conclusion to be deduced from these facts is, that cells with unchanged blood globules only show themselves a -short time after eating, and that the granule-cells which proceed from these are almost always present, although in greater number in animals which have fasted a considerable time. If any animal were examined at the proper time, one would be astonished at the uncommon quantity of de composing blood globules; for in such a case the whole red part of the pulp consists (so to speak) of nothing but golden yellow or blackish corpuscles, which are the different metamorphoses of blood corpuscles already mentioned.
Of the ultimate destiny of the blood cor puscles so metamorphosed, thus much is certain,—that they are decomposed and dis solved ; but, on the other hand, it is difficult to make out what is the destiny of the cells which ustially enclose them We have already seen above that these cells occur in the splenic vein, the vena portw, and the inferior cava, and it is thence -questionable whether all these cells may not possibly pass into the blood. It is difficult to give an answ er to this. Thus much I consider to be made out : —that -cells with unchanged blood globules, and yellow, brown, or blackish-yellow granule cells, only exceptionally and seldom pass into the blood of the splenic vein, or beyond ; since, in the first place, these cells are, upon the whole, rarely found in the blood ; secondly, their occurrence in the spleen is demonstrably very frequent. On the other
hand, as to the colourless granule-cells which finally arise from the cells containino. blood corpuscles, it is not made out whether they remain in the spleen or enter the blood. Supposing the first of these to be the case, they may either abide a considerable time in the pulp, and then in a certain manner serve as parenchyma-cells, with which they have a great similarity, or they inay experience a dissolution, and altogether disappear. In the second case, one may imagine that they are converted into lymph corpuscles, with which they have, to some extent, a great similarity, or that they undergo a solution in the blood of the portal vein and the rest of the circula tion. I own that I cannot hazard a decision. It is certain that colourless granule-cells occur in the blood as well as in the spleen ; but it is also certain that they are much more frequent in the spleen, and that, as regards the blood of extravasation which un dergoes metamorphosis, it may be definitely stated, that its products for the most part remain in the same place.
So much for my experience of the decom position of blood corpuscles in the spleen. Simultaneously with myself, Professor Ecker, of Basle, made similar observations, which likewise referred to a destruction of blood corpuscles, and which, soon after, lent an ad ditional light to mine.* In contradiction to this, however, Gerlach has lately uttered the opinion that my observations allude to the formation of colored corpuscles within colorless ones; so that he explains the forms of cells which are found in the spleen in precisely the reverse way, and supposes that the cells with golden yellow granules are the younger, and those with unchanged blood corpuscles the elder ; that is, that they are those in which the blood corpuscles have completely developed themselves, and from which they are ready to be expelled or set free. So that if Gerlach be correct, the relation of the blood corpuscles to the spleen is precisely the reyerse of that which I have stated, and they begin there in great quantities ; and it thus becomes important to inquire whose opinion is the correct one. But if my ex periments upon the behaviour of the blood corpuscles in the spleen have no other con sideration, this merit, at least, remains to them, that they accurately set forth the anatomical facts, and in this manner have already sufficed to refute such false theories as that of Gerlach. In point of fact, Gerlach is altogether wrong when he supposes that the golden yellow granules are changed into blood globules ; for this can in no way be proved, but very easily the contrary. He is equally in error in adducing, as a ground for this view, that blood corpuscles begin as cells in the embryonal liver,—a statement which is altogether incorrect. And when he finally adduces that since, according to Harless t, the blood corpuscles 0,re destroyed by the alternating influence of nitrogen and carbonic acid, a second kind of solution of these in the spleen cannot be conceived ; it need only be remarked that this theory of Harless's is not in the least proved as regards the living organism. So, also, Virchow I has expressed himself as partially against mine and Ecker's account; since, though he does not at all doubt the dissolution of blood corpuscles, yet he altogether denies the origin of cells around heaps of blood corpuscles. This statement is only explicable by supposing that the Mam malia and Reptilia, in whom this pheno menon can be seen as plainly as could be wished, were not examined by Virchow. Besides, I do not maintain that the effused blood always forms cells containing blood corpuscles ; only I hold it as a fact established beyond all doubt, that this very frequently happens in the spleen as well as in extrava sations in the lungs, lymphatic glands, brain, and thyroid body ; and while I believe that the formation of cells around these several effusions is not an equivalent fact, yet it is altogether certain that blood globules enclosed in cells undergo a more speedy dissolution than if they remain free.