58 



ADIPOSE TISSUE. 



same distinct arrangement of an appropriate 

 organ, but simply masses of adipose, or rather 

 sebaceous matter, interposed between the at- 

 tached surface of the serous membranes and 

 the adjoining or the contained organs. 



Fat occurs in a third modification in the 

 marrow of bones. The adipose granules, which 

 are soft, whitish-yellow, and oleaginous, are 

 here contained in a peculiar membrano-cellular 

 web, forming numerous vesicles, which may be 

 regarded as an ultra-osseous adipose tissue. It 

 is a remarkable proof of the influence of the 

 vital principle that during life the substance of 

 the bones is never tinged with this animal oil, 

 but the moment life is extinct, the marrow 

 begins to transude and impart to the bones a 

 yellow tint and a greasy aspect. 



Fat, though chiefly observed to occur in the 

 bodies of animals, is nevertheless not confined 

 solely to these bodies. Thus not only do va- 

 rious kinds of oil and consistent oleaginous 

 matter occur in certain vegetables, but sub- 

 stances similar even to tallow are found in 

 some vegetable productions. A sort of 

 tallow is obtained from the Valeria Indie a, a 

 forest-tree of the camphor family, indigenous 

 in the Indian Archipelago. In a species of 

 croton indigenous in China, namely, the croton 

 sebiferum of Linnaeus, the stillingia of Mi- 

 chaux, or tallow-tree, the seeds are covered 

 with a quantity of fat, bearing so close a re- 

 semblance in all its properties to tallow, that it 

 is used by the Chinese in the manufacture of 

 candles ; and the fruits of the aleurites triloba, 

 a native of the Sandwicli Islands, of the same 

 natural family with the croton, are the candle- 

 nuts of the inhabitants of these remote regions. 



It is chiefly in the subcutaneous layer that 

 the organization of the adipose membrane has 

 been investigated. The constituent vesicles or 

 bags consist of firm, tenacious, ligamentous, 

 gray, or whitish-gray coloured substance, mu- 

 tually united by means of delicate filamentous 

 tissue. These vesicles or sacs receive arterial 

 and venous branches, the arrangement of which 

 has been described by various authors, from 

 Malpighi, who gave the first accurate account, 

 to Mascagni, to whom we are indebted for the 

 most recent. According to Malpighi,* the 

 bloodvessels divide into minute ramifications, 

 to the extremities of which are attached the 

 membranous sacs, containing the globules of 

 fat so as to bear some resemblance to the leaves 

 attached to the footstalks of trees. These ve- 

 sicular or saccular arteries are afterwards di- 

 vided into more minute vessels, which then 

 form upon the vesicular sacs a delicate vascular 

 network. According to Mascagni, who repre- 

 sents these vessels in accurate delineations, the 

 furrow or space between each packet con- 

 tains an artery and vein, which, being subdi- 

 vided, penetrates between minute grains or adi- 

 pose particles, of which the packet is composed, 

 and furnishes each component granule with a 

 small artery and vein. The effect of this ar- 



rangement is that each individual grain or 

 adipose particle is supported by its artery and 

 vein as by a footstalk or peduncle, and those of 

 the same packet are kept together not only by 

 contact, but by the community of ramifications 

 from the same vessel. These grains are so 

 closely attached that Mascagni, who examined 

 them with a good lens, compares them to a 

 cluster of fish-spawn. Grutzmacher found 

 much the same arrangement in the grains and 

 vesicles of the marrow of bones.* 



It has been supposed that the adipose tissue 

 receives nervous filaments; and Mascagni con- 

 ceives he has demonstrated its lymphatics. Both 

 points, however, are so problematical, that of 

 neither of these tissues is the distribution known. 



The substance contained in these vesicles is 

 entirely inorganic. Always solid in the dead 

 body, it has been represented as being fluid 

 during life, by Winslow, Haller, Portal, Bichat, 

 and most authors on anatomy. The last writer, 

 indeed, states that under the skin it is more 

 consistent, and that in various living animals 

 he never found it so fluid as is represented. 

 The truth is that in the human body, and in 

 most mammiferous animals during life, the fat 

 is neither fluid nor semifluid. It is simply 

 soft, yielding, and compressible, with a slight 

 degree of transparency, or rather translucence. 

 This is easily established by observing it during 

 incisions through the adipose membrane, either 

 in the human body or in the lower animals. 



The internal or sebaceous fat, however, espe- 

 cially that interposed between the fat of the 

 serous membranes, is much more consistent and 

 solid. The reason of these differences will be 

 understood from what is now to be stated re- 

 garding the proximate principles of animal fat. 



The microscopical and atomical structure of 

 fat has recently formed the subject of investi- 

 gation by M. Raspail.f By placing a portion 

 of lacerated fat upon a sieve, with an earthen 

 vessel below it, and directing upon it a stream 

 of water, numerous amylaceous granules are de- 

 tached and pass through the sieve, and after 

 foiling to the bottom of the water afterwards 

 rise to the surface, in the form of a crystalline 

 powder, as white as snow. When these par- 

 ticles are collected by scumming, and dried, 

 they form a starchy powder, though soft and 

 somewhat oleaginous to the touch, and which 

 does not reflect the light in a manner so cry- 

 stalline as an amylaceous deposit does. 



According to M. Raspail,' when examined 

 microscopically, these granules present forms 

 and dimensions varying in different animals, 

 in the same animal and even in animals of dif- 

 ferent ages, but in all clearly resembling grains 

 of fecula. In the human body these particles 

 are polyhedral and not susceptible of isolation. 

 As they are more fluid also than in other 

 animals, it is necessary to immerse the portion 

 subjected to examination in nitric acid or 

 liquor potasses, either of which has the effect 

 of consolidating the inclosed or central portion 



* De Qmento, Pinguedine, et Adiposis Ductibus, 

 p. 41. 



* De Ossium Medulla, Lips. 1758. 

 t Repertoire Generale d'Anat. 1827. 



