230 WHAT IS LIFE 



conveying hereditary traits. It is Jacques Loeb's 

 finding: "The analysis of the process of fertilization 

 by the spermatozoon shows that we must dis- 

 criminate between two kinds of effects, the hereditary 

 effect and the activating or developmental effect."^^ 



Biologists today are generally agreed that the 

 factors, or carriers, of heredity are the chromosomes, 

 bodies, or structures, that are found in the nucleus of 

 the egg and in the head of the spermatozoon; and 

 which may be identified under suitable conditions.^" 



"Chromosomes" are thought to be the carriers of 

 individual hereditary traits; individual hereditary 

 traits being distinguished from the general traits of 

 species heredity. 



As the name itself indicates, chromosomes furnish 

 a purely morphological conception of heredity; and, 

 of course, no biologist supposes that visible structures 

 can supply an ultimate conception of heredity. 

 {See pp. 258 and 259.) 



Henry Fairfield Osborn (the famous paleontologist 

 who has been freely quoted) some years ago urged 

 an "energy" conception of heredity — "and away from 

 the matter and form conceptions." Osborn said that 

 "we may imagine that the energy which lies in the 



*^ The Mechanistic Conception of Life, 158. 



^^ See August Koehler, Zeitschrift fiir wissenschaftliche Mikrosko-pie, XXI, 

 129; W. T. Bovie, Journal of Medical Research, XXXIX, 247. 



