30 UNIVERSALITY OF DEGENERATIVE EVOLUTION 



These various instances of cellular adaptation 

 called " heteromorphosis " by Loeb, are outside 

 the limits of our present researches, for reasons 

 which we have already given. 



The law of universal degenerative evolution 

 applies only to the transformations of organs, and 

 not to their original formation in either individuals 

 or species, under normal or abnormal conditions. 



SECTION I. 

 Transformation of organs of animals. 



2. Transformation of homodynamic organs in 

 the individual. 



In order to study the degenerative evolution 

 exhibited in the specific modifications of the 

 organs of an individual, it is necessary to choose 

 homodynamic organs that are numerous, and conse- 

 quently small enough to undergo different kinds of 

 transformation fitted to the functions they may 

 have to serve in the "different parts of the body. 



The numerous appendages of the cray-fish form 

 an extremely interesting study of this. kind. The 



parts of a bone do not unite after fracture. In that case a com- 

 pleted joint with cartilage ligament and synovial membrane may 

 be formed in the neighbouring tissues under the influence of the 

 new stimuli. In extra uterine gestation the placenta is formed 

 upon some abdominal organ. When this occurs, the unusual 

 stimulus is sufficient to cause the cells of an abdominal organ 

 to form a perfectly specialized organ of a nature foreign to their 

 normal life. 



