Odier on the Chemical composition, S^c. 101 



Art. XV. — Memoir on the Chemical Composition of the 

 Corneous parts of Insects. By M. Augustus Odier* 

 With some additional remarks and experiments, bi/ i. G. 

 Chidluen, Esq. F. R. S. L. S. &c. 



Experiments, often repeated, have long since taught us the che- 

 mical composition of the bones of vertebrated animals of the first 

 order. The skeletons of animals of inferior rank in the zoological 

 scalcj have also been subjected to chemical analysis, for the pur- 

 pose of comparison with those of the former, whence we have ob- 

 tained a knowledge of the component parts of the bones of fishes, 

 the shells of mollusca and Crustacea, and the hard portions of the 

 zoophyta. 



The solid parts of the bodies of insects, however, have never 

 been made the subject of chemical research ; naturalists have been 

 satisfied with likening them to those animal substances which 

 they most nearly resemble either in their functions, or natural ap- 

 pearance ; hence some, comparing them to the bones of vertebrated 

 animals, have named them osseous parts, and have even ventured 

 to call the whole assemblage the skeleton of the insects ; others, 

 on the contrary, likening them to the integuments of vertebrated 

 animals, have considered them as hardened skin, or a matter ana- 

 logous to horn. 



In undertaking to investigate the chemical composition of these 

 organs, my object is not to support either of these two opinions; 

 I shall examine the substances with the sole view of ascertaining 

 their composition, without seeking to associate them with any par- 

 ticular organ of the superior animals. 



The analysis of some Crustacea, by M. M. Merait, Guillot, 

 and Chevreul, are the only works that have been published, as far 

 as I know, on animals approaching the class of insects; and 

 amongst these much discrepancy exists as to the composition of 

 their integuments.* 



* Translated from the " Memoiresdela Societe d'hist. nat. de Paris," vol. 1. 



+ Has M. Odier never heard of Mr. Hatchett's elaborate " Experiments and 

 Observations on Shell and Bone," or his " Chemical Experiments on Zoo- 

 l)hyta ?" See Phil. Trans. 1799 and 1800. C. 



