448 Evolution and Adaptation 



accomplished by the normal method of fertilization that is 

 here absent. This may mean no more than that as yet we 

 have not found all the conditions necessary to supply the 

 place of the spermatozoon. 



In our study of the phenomena of adaptation we have 

 found that sometimes the adaptation is for the benefit of the 

 individual and at other times for the benefit of the species. 

 May it not be true also that the process of sexual reproduc- 

 tion has more to do with a benefit conferred on the race 

 rather than on the individual ? In fact, Weismann has 

 elaborated a view based on the conception that the process 

 of sexual reproduction is beneficial to the race rather than to 

 the individual. His idea, however, is not so much that the 

 result is of direct benefit to a particular species, as it is ad- 

 vantageous to the formation of new species from the original 

 one. In a sense this amounts, perhaps, to nearly the same 

 thing, but in another sense the idea involves a somewhat 

 different point of view. 



According to his view " the deeper significance of conjuga- 

 tion " and of sexual reproduction is concerned " with the 

 mingling of the hereditary tendencies of two individuals.'' 

 In this way, through the different combinations that are 

 formed, variations which he supposes are indispensable for the 

 action of natural selection originate. The purpose of the 

 sexual process is solely, according to Weismann, to supply 

 the variations for natural selection. If it be asked how this 

 process has been acquired for the purpose of supplying nat- 

 ural selection with the material on which it can work, we find 

 the following reply given by Weismann. " But if amphi- 

 mixis [by which he means the union of sex-cells from different 

 individuals] is not absolutely necessary, the rarity of purely 

 parthenogenetic reproduction shows that it must have a wide- 

 spread and deep significance. Its benefits are not to be 

 sought in the single individual ; for organisms can arise by 

 agamic methods, without thereby suffering any loss of vital 



