326 Cell as Basis of Organic Activity 



The Inheritance of Acquired Characters. — Only recently has 

 the founder of this theory, Lamarck, gained the recognition which he 

 deserves as a biologist. Lamarck lived in France from 1744 to 1829 

 and began his career as a botanist. At the age of 50, he became a 

 zoologist, and it was during this latter period that he did his best known 

 work. During his studies, Lamarck saw that species varied with the 

 changing environment, that there are evident relationships among dif- 

 ferent species, and finally that species develop progressively. All these 

 conclusions are well founded, but unfortunately Lamarck's contempo- 

 raries held him in contempt as a scientist. In part this was due to 

 his unfortunate manner of writing and in part to the active opposi- 

 tion of certain important scientists. Lamarck sought an explanation of 

 these facts which he observed, and in so doing he developed his theory 

 of the inheritance of acquired characters. 



According to this theory, environmental conditions affecting an ani- 

 mal produce changes which are transmitted to the offspring. One 

 classical example is the long-necked giraffe. It was presumed that some 

 deerlike creature, tiring of feeding on herbage, started reaching for 

 leaves on trees. This continuously stretched the neck, and after a num- 

 ber of generations long-necked animals were produced. Other ex- 

 amples were cited ; among them were the blind animals of caves. 

 Through generations of not using eyes in the Stygian blackness of the 

 caves, the eyes supposedly were gradually lost. This principle has 

 often been called the Law of Use and Disuse for the above-stated reasons. 



This theory was adhered to by Erasmus Darwin, and perhaps it 

 was through him that Charles Darwin considered that this theory was 

 probably valid, though with reservations. 



It is now known that the theory of inheritance of acquired charac- 

 teristics as proposed by Lamarck is incorrect. There are many ex- 

 periments which definitely show the lack of validity of this theory. 

 For example, the Chinese bound the feet of women for many genera- 

 tions, but the feet never became small and disfigured. The Ubangi 

 have stretched the lips of women ; nevertheless girl babies still are 

 born with normal lips. Under more controlled conditions, the tails 

 of generations of rats have been cut off, still the rats have long tails 

 at birth. These experiments show that Lamarck's explanation was 

 incorrect ; however, the question of the inheritance of acquired charac- 

 teristics is still an intriguing one, and has never been completely ruled 

 out. With the recent work on environmental influence on the plasma- 

 genes of cytoplasm, this theory is again being discussed. 



