FROM LAMARCK TO ST. HILAIRE. 



First Law. — Life by its internal forces tends 

 continually to increase the volume of every body 

 that possesses it, as well as to increase the size of 

 all the parts of the body up to a limit which it 

 brings about. 



Second Law. — The production of a new organ 

 or part results from a new need or want, which 

 continues to be felt, and from the new movement 

 which this need initiates and causes to continue. 

 (This is the psychical factor in his theory, which 

 Cope later has termed Archcesthetism.) 



Third Law. — The development of organs and 

 their force or power of action are always in direct 

 relation to the employment of these organs. (At 

 another point he expands this into two sub-laws : 

 " In every animal which has not passed the term of 

 its development, the more frequent and sustained 

 employment of each organ strengthens little by 

 little this organ, develops it, increases it in size, 

 and gives it a power proportioned to the length of 

 its employment ; whereas the constant lack of use 

 of the same organ insensibly weakens it, deteriorates 

 it, progressively diminishes its powers, and ends by 

 causing it to disappear." This is now known as 

 the Law of Use and Disuse, or Kinetogenesis.) 



Fotirth Law. — All that has been acquired or 

 altered in the organization of individuals during 

 their life is preserved by generation, '.nd trans- 

 mitted to new individuals which proceed from those 

 which have undergone these changes. 



