DEGRADATION OF ORGANISATION 105 



Thus on traversing the chain of animals from the most perfect to 

 the most imperfect, and on examining in turn the various systems 

 of organisation distinguished in the course of this chain, the degrada- 

 tion of organisation and of each organ up to their complete disappear- 

 ance is seen to be a positive fact which we have now verified. 



This degradation comes out even in the nature and consistency of 

 the essential fluids and flesh of animals. For the flesh and blood of 

 mammals and birds are the most complex and animahsed materials 

 that can be obtained from the soft parts of animals. Hence after 

 the fishes these materials are progressively degraded until in the soft 

 radiarians, the polyps and the infusorians, the essential fluid has only 

 the consistency and colour of water and the flesh is nothing more than 

 a gelatinous scarcely animahsed material. The bouillon made from 

 such flesh would scarcely be found very nourishing or strengthening 

 by any one who tried to Uve upon it. 



Whether or no we recognise these interesting truths, they will never- 

 theless always be forced upon the attention of those who closely 

 observe facts, and who, overcoming prevailing prejudices, consult the 

 phenomena of nature and study her laws and regular procedure. 



We shall now pass to the examination of another kind of subject, 

 and shall endeavour to prove that the environment exercises a great 

 influence over the activities of animals, and that as a result of this 

 influence the increased and sustained use or disuse of any organ are 

 causes of modification of the organisation and shape of animals and 

 give rise to the anomalies observed in the progress of the complexity 

 of animal organisation. 



