152 ANATOMY. 



nutrimental matter, which, during the metamorphosis., particularly 

 during the pupa sleep, is absorbed like the fat of the lethargic mammalia 

 during their hybernation. But the degree of reference the function of 

 the liver has to the preparation of the fat is sufficiently well known 

 from the example of the lethargic mammalia, therefore the above opi- 

 nion, when we consider the small size of the biliary vessels supplanting- 

 the liver, or the treatment of these vessels as kidneys, a view also 

 recently promulgated, may possibly have many supporters. 



The nature of this fatty body is in so far uniform that it consists of 

 shreds, which upon microscopic investigation are found to be constituted 

 of small globules of animal aboriginal matter. This is the only cha- 

 racter this fatty mass presents upon the closest investigation ; exteriorly 

 it is surrounded by delicate membranes, which consequently may be 

 compared to the membranes of the cellular texture, but the lens does 

 not show it very distinctly, from its transparency, delicacy, and tex- 

 turelessness. Ramdohr, who considered the fatty mass as plastic lymph, 

 obtained from experiments upon that of the Gastrophaga quercus 

 the following result: it melted in boiling water, effervesced with 

 sulphuric acid, at the same time smelling like burnt horn, and in cold 

 water was precipitated in white flocks; heated over a lamp it hardened 

 into a white firm mass, swelled up upon the application of greater heat, 

 and then burnt away, dispersing a stinking vapour. According to my 

 experiments, made with the large flabby fatty mass of Cossus ligni- 

 perda, it melted in a spoon over a lamp into a perfectly clear trans- 

 parent yellow liquid, which paper instantly absorbed, and was rendered 

 transparent by it like fat ; it had a peculiar smell, like that of freshly 

 opened caterpillars ; its taste was fatty and insipid. Upon increased 

 heat it boiled up in bladders but did not become firm, or else it consumed 

 to ashes. Laid fresh in hot water it became softer, more transparent, 

 and particles of it floated on the top like oil. 



These very contradictory results tend at least to prove that the fatty 

 substance in different insects consists of very different constituents, 

 which is the more striking as both experiments were made from insects of 

 the same order, in which they even approach very near each other. Pro- 

 bably Ramdohr's caterpillar had been long immersed in spirits of wine, 

 thus consequently, and by the additional influence of heat, the fat parts 

 had separated, and only the cellular portion of the enveloping mem- 

 branes remained. 



The entire fatty mass forms a reticulated meshy web, which enve- 



