BARON CUVIER. 71 



insects, the vessels which receive the air are 

 ramified to infinity, in order to carry it to every 

 part of the body without exception, and this is 

 what is called respiration by means of tracheae. 

 Lastly, the zoophytes, with the exception of 

 echinodermes, have no apparent organ of re- 

 spiration.'* 



In the third portion of this opening lecture, 

 the affinities of organs are described, and their 

 manner of acting on each other. •' Of what 

 use,"- says M. Cuvier, "would sensation be to 

 us, if muscular force did not help it, even in the 

 most trifling circumstances ? What use could 

 we make of touch, if we could not carry our 

 hands towards the palpable object? and what 

 should we behold if we could not turn our eyes 

 or head at pleasure ? It is on this mutual de- 

 pendence between the functions, and on this 

 reciprocal aid, that the laws are founded which 

 determine the affinities of the organs of animals ; 

 which affinities are as necessary to them, as 

 metapliysical or mathematical laws are to other 

 parts of the creation. For it is evident, that a 

 suitable harmony between those organs whicli 

 act upon each other, is a necessary condition to 

 the existence of the being to which they belong j 

 and that if one of these functions were modified 



F 4 



