During the periods of boyhood and youth fat continues very sparing in the adipose tissue, and especially in the male sex. After puberty, however, it becomes more abundant, especially in females. After this period the deposition of fat depends more or less on the habits of the individual, as to eating and drinking and corporeal exertion. In general the deposition of fat becomes more copious and general after the age of forty or forty-two than previously.
From these several facts it appears to result that fat is to be regarded as a secretion by the capillary vessels of the adipose tissue from the blood, and that the tissue and its vessels are to be distinguished from the fat or the matter secreted in the relation of vital agents and organic products. Upon the whole the idea of Haller as modified by Mascagni regarding the origin of the fat appears to be the most probable, viz. that, while the arteries secrete an imperfectly formed oily fluid, the thinner parts are absorbed either by lymphatics or by veins, and the residue is left in a more con sistent and solid form.
I think, in conclusion, that, taking all the circumstances already stated into consideration, it may be inferred that adipose matter, or its constituent elements exist in the blood, chiefly as complementary elements of the albuminous, gelatinous, osmazomatous, or gelatino-albu ininous principles employed in the nutrition of the several tissues ; and that, as the carbon, hydrogen, oxygen, and azote are employed in the formation of the latter tissues, the great excess of carbon, and the smaller excess of hy drogen and oxygen, not employed in the for mation of these tissues are arranged by the capillaries in such proportions as to form adi pose matter ; and that this adipose matter, though fluid, when first becomes more consistent and fixed after deposition in its appropriate tissues.
The pathological conditions of the adipose tissue.
1. Inflammation.—From various facts, and especially, observing the phenomena of certain cases of what have been denominated diffuse inflammation of the cellular membrane, I for merly inferred that the peculiar phenomena of certain intense and malignant forms of this disorder, depend on inflammation not of the cellular membrane, but of the adipose tissue.
This conjecture I have since had opportunities of completely verifying as to certain, if not the majority of cases of diffuse inflammation.
a. In cases of diffuse inflammation affecting the arm, the inflammation has , spread along the adipose membrane, producing sero-puru lent suppuration and sloughs of the adipose tissue. In cases of inflammation at the verge of the anus, the disease spreads along in the same manner, and affects, almost exclusively, the adipose tissue around the anus and rectum, and along the glutcei muscles. It is in the same manner that the adipose cushion, with which the bloodvessels are surrounded, is oc casionally the seat of a species of bad inflam matory action terminating in fetid and sloughy' suppuration.
That these forms of diffuse inflammation truly depend on inflammation of the adipose* membrane, I must further maintain, from the fact that the disease occurs not only in the ex ternal adipose cushion, but in the internal or sebaceous fat. I have seen an example of in flammation in the adipose cushion surrounding the left kidney, in which the whole of this substance was converted into an ash-coloured,' fetid, semifluid pulp, mixed with shreddy fila ments, and in which this suppurative slough ing process had opened a passage from the fat of the left kidney into the interior of the trans verse arch of the colon. The instance of in flammation and subsequent mortification of the adipose membrane surrounding both kidneys, detailed by Dr. Thomas Turner, in the fourth volume of the Transactions of the College of Physicians in London, is an example of the same species of disease. In the case witnessed by my self, the disease gave rise to the usual symptoms said to attend diffuse inflammation. Though no great degree of pain was felt, the pulse was • quick and small, the tongue brown and dry, the countenance dingy and lurid, and the eyes • heavy, the bowels difficult to be affected by medicine, the urine scanty and high-coloured, and at length suppressed ' • and the patient, after muttering delirium and typhomania on the second day of attack, with subsultus tendi num, passed into a comatose state, which ter minated on the fourth day in death.