Report on the progress of human anatomy and physiology in the year 1844-5 / [Sir James Paget].

  • James Paget
Date:
1846
Catalogue details

Licence: Public Domain Mark

Credit: Report on the progress of human anatomy and physiology in the year 1844-5 / [Sir James Paget]. Source: Wellcome Collection.

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    of the capillary vessels on the exterior of the vesicles or other collections of cytoblasts in the glands without, just as in those with, ducts. Thus, the glands without ducts possess all the apparatus which, in the true glands, is provided for secretion. They differ from them in that the formation of cells around their cytoblasts is exceptional, and that their secretion is poured into closed cavities, not into open canals. Assuming then, that the common occupation of these organs consists in withdrawing from the blood some material which they may (probably after some elaboration) discharge into it again,—the next question is,—What is more particularly the function of each of these glands? In answer only one thing is proved ; Mr. Simon’s observations prove that in the liybernating ani¬ mals the thymus forms in itself a store of fat, to be consumed in the mainten¬ ance of the temperature during hybernation; and this is more than ever yet was proved of any of these glands. His and former observations also render it highly probable that in other than the hybernant animals, the thymus, during all its temporary existence, is occupied in sequestrating some material from the blood to be restored to it again, in the same or (more probably) some other form. He believes that this material is always such as may be consumed in the service of respiration, “ the thymus gland fulfilling its use as a sinking fund in the service of respiration.” [But the evidence appears to me insufficient for this conclusion, or even opposed to it 5 for when in hybernation the gland performs this function, and performs it in the highest degree, it is temporarily adapted for it, not by temporary development, but, as all the analogies of the formation of fat in other cases show, by temporary degeneration. The formation of an extraordinary quantity of fat in any part expresses a defective nutrition of that part; and when the thymus of hybernants accumulates fat at the approach of their winter sleep, it is probably rather because some process in general nutrition to which it before ministered is ceasing, than because it is now about to discharge in an extraordinary degree its ordinary function. I should regard the fatty degeneration or fatty atrophy of the thymus at the approach of each winter-sleep as an annual recurrence of a process analogous to that atrophy by diminution or total removal of substance which takes place once for all in the animals in which the thymus is not persistent. In each case the atrophy is an indication that the necessity for the ordinary acts of the thymus has ceased; but in the hybernants it is for new circumstances made to minister to a new purpose, till, at the cessation of the winter-sleep, and the recom¬ mencement of new growth, it begins again to be truly developed, and to form the more highly organic azotized compounds which it may restore to the blood for the nutrition of the fresh-growing tissues.] For the thyroid gland, Mr. Simon believes (chiefly on the evidence of its comparative anatomy), that it supplies, in its simplest state, a vascular diverti¬ culum to the stream of the cerebral circulation, and that in its higher develop¬ ment, its secretion bears some essential relation to the nutrition of the brain, such that, for instance, while the brain is at rest it may be separating from the blood the same materials as the brain in action takes from the blood. In like manner he holds the spleen to be as a diverticulum to the syste¬ matic circulation when the vessels are filled after taking food; and, by the secretion of the Malpighian corpuscles, an organ in which nutritive matter may be stored up till the system needs it. And, lastly, he thinks the renal capsules may have with the generative system some such relation in alternat¬ ing secretion as he supposes the thyroid gland to have with the brain. In the place of these several theories, Oesterlen, in a long discussion, enunciates but one, and that not anew one; namely, that the acts of the glands without ducts are the taking of fluid from the blood, from which as a cyto- blastema their cytoblasts are formed ; and that these, after their completed development, liquefy and restore to the blood a material more fitted for nutri¬ tion than that which it gave for them. [And indefinite and incomplete as this theory is, I must confess it appears to me to express all that can as yet be con¬ sidered very probable in the general physiology of the glands without ducts.]