1*76 INTERNAL ANATOMY OF INSECTS. 



of which we are speaking, by the name of Jibrinc. By 

 the abundance of azote or nitrogen that enters into its 

 composition, it possesses a character of animalization 

 more marked than any other animal substance ; and its 

 elements are so approximated in the blood, that the 

 slightest stagnation causes them to coagulate : and the 

 muscles are without d&ubt, in the living subject, the 

 only organs that can separate this matter from the mass 

 of blood, and appropriate it to themselves 3 . The 

 primary bundles of muscles are formed of the simple 

 fibres, and the secondary are the result of an aggrega- 

 tion of the primary. The smaller bundles are not al- 

 ways exactly parallel to each other, but must in many 

 cases diverge more or less, to produce those variations 

 in shape observable in the muscles themselves : there 

 are intervals therefore between the bundles, which in 

 some animals are filled by a cellular substance 5 . Pro- 

 bably much of this statement will apply in most in- 

 stances to the muscles of insects, but we may conclude 

 that the globules that form them are infinitely smaller . 

 Lyonet has given some interesting observations with 

 regard to those of the caterpillar of the Cossus : he de- 

 scribes them as of a soft transparent substance, capable 

 of great extension, covered and filled by silver tubes of 

 the bronchia, penetrated by the nerves, and containing 

 oily particles. Each muscle was enveloped in mem- 

 brane, and was composed of many parallel bands, con- 

 sisting of bundles of fibres enveloped likewise in sepa- 

 rate membranes. The fibres themselves, (but it is doubt- 

 ful whether he arrived at the ultimate term of muscular 

 fibre,) in a favourable light and under a good magnifier, 



a Cuv. ubi mpr. 90-. b Cuv. Ibid. i. 89. 



e See above, p. 85. 



