The remaining contents of the follicle form a soft pulpy mass. This is remarkably con trasted with the contents of the neighbouring lacteals, in the fact that it is always of a pale, semi-transparent, greyish colour ; while the latter are, during digestion, of a brilliant white. The application of reagents under the microscope shows this greyish pulp to be composed of a proteinous substance closely akin to albumen. The addition of water causes it to swell up, and effects its partial solution. And as regards its structure, the mass consists of a moderate quantity of fluid, mingled with a variety of cells. These, however different in their characters, may probably be all reduced to various forms of cell-growth, on the one hand; and various stages of the retrograde solution of blood-cor puscles, on the other. The latter process, though by no means uncommon, appears always due to an extravasation of a more or less accidental character. It is the cell growth which constitutes the specific histo logical character of these albuminous contents of the follicle.
The cell-growth ranges from distinctly nu cleated cells, of TA-6th of an inch in diameter, to cells of about one-half, and through these to nuclei of barely one-third, the above size. The latter, however, are of nearly the same bulk as those contained in the largest cells. Hence it vvould seem that the process of growth which these differences indicate, consists chiefly in the isolation and removal of the cell-wall, from its previously close apposition around the nucleus. In the Sheep, however, Koelliker has sometimes observed an endogenous multiplication of large cells, by a subdivision of their nuclei. And in other specimens from the same animal, he has noticed what is very possibly the opposite extreme of the cell-life : — the cavity of a large cell filled with large angular corpuscles. These corpuscles are sometimes nucleated ; they have albuminous reactions; and they appear to be produced from the ordinary cells of the pulp. They ultimately disappear.
The function of the agminate follicles it is impossible to specify. Few organs in the body have been the subject of more numerous speculations:—speculations, the absurdity of most of which renders them unworthy of any serious mention. And hence, although what we know respecting the structure of these organs justifies (or rather requires) some attempt to indicate their physiological import, the mistakes of others may ',yell teach us how much caution is requisite in making such conjectures. They are, at most, mere
guesses at truth.
The contents of the follicle have just been stated to be composed of a cell-gr, owth that lies in contact with a large vascular surface. Hence it is in the reaction of these innu merable minute agents on a copious and rich nutritional fluid exsuded from the blood, that vke must look for the chief office of the follicle. The fact of various stages of cell-life being present simultaneously, appears to in dicate, that the cells do not merely select certain materials, but more or less produce them ; by a process which, directly or indi rectly —by absolutely consuming their tissue, or otherwise— involves their own decay and death. So far, then, the agminate follicle, which closely resembles the vascular gland in its structure, might be conjectured akin to it in its function ; — that function being a choice from the nutritional fluid of certain of its con stituents, which, after undergoing a metamor phosis, are subsequently returned into the general current of the blood.
But such a view omits to recognize some of the circumstances it ought to explain. And it especially neglects one which must be sup posed of great importance : namely, the situa tion of the follicle ; or, in other words, its peculiar relation to the cavity of the intestine.
It is obvious that the position of the agmi nate follicle with respect to the intestinal canal will admit of a double interpretation. On the one hand, the materials on which its enclosed cells have to act, will probably be derived from the contents of the alimentary canal, as well as from the blood. And on the other hand, they may be ultimately excreted from the body through the intestine, as well as re turned into that system of closed canals which the blood vessels compose.
The degree in which the intestine forms the channel of such an ingress and egress, must of course depend upon the directness and effi ciency of the communication between its ca vity and that of the follicle. Hence, where the two are in such close contiguity to each other as in the case of the agminate glands of the human subject, we may presume that an efficitnt transudation of this two fold nature really does obtain. But where, as in some of the follicles of the Calf, the cavity of the intestine is separated from that of these minute sacs by the inter vention of a thick compound mucous mem brane, it is ciifficult to avoid the conclusion ; that a transit of their fluid contents, in either, direction can only obtain to a conipa ratively small amount.