12 EVOLUTIONS OF ORGANIZATION. 



composition, and the conditions of respiration 

 having been thus modified, actual forms had to 

 differ in organization from their ancestors of ancient 

 times, and that according to the degree of the 

 modifying force." l 



Lamarck, who next claims attention, has given 

 the summary of his doctrine in language so brief and 

 clear, that I may quote his own words. He lays down 

 four principles : " I. Life, by its own forces, tends 

 continually to increase the volume of the whole body 

 which possesses it, and to extend the dimensions 

 of its parts up to a limit which it determines. 2. 

 The production of a new organ in an animal body 

 results from a new want supervening, which con- 

 tinues to make itself felt, and from a new move- 

 ment which this want gives birth to, and continues. 

 3. The development of the organs and their force 

 of action are constantly in ratio of the employment 

 of these organs. 4. All that has been acquired, 

 laid down or changed, in the organization of the 

 individuals during the course of their life, is con- 

 served by their generation and transmitted to the 

 new individuals proceeding from those which have 

 undergone those changes." 2 



1 Me"moires de 1'Academie Royale des Sciences, XII., 63. Isidore 

 Geoffrey St. Hilaire, Histoire Naturelle Generate, II., p. 416. 



2 Lamarck, Hist. Nat. des Animaux sans Vertebres. 3rd Edition, 

 P. 57- 



