248 Fertilisation and Hybridization 



ment for the single individuals, or by a sacrifice of all 

 the individuals that do not quite meet all the requirements. 



This service of sexual reproduction is evidently not 

 limited to a single generation. It exercises its influence 

 throughout successive generations, and it is probably in- 

 different whether the effect follows directly, or whether it 

 manifests itself in the course of time. Even without that, 

 the complete utilization of all given possibilities requires, 

 as a rule, more individual beings than are born in a single 

 generation. And with this, the otherwise strange fact is 

 explained, that the exchange of the units does not imme- 

 diately follow fertilization, but only takes place a short 

 time before the succeeding period of fertilization. But 

 obviously an exchange, ruled by laws of chance, could not 

 benefit a given isolated individual or, more correctly speak- 

 ing, it would most likely, just as frequently be harmful 

 as useful. It can only be of use in connection with an 

 increase in the number of individuals, for it is its task to 

 bring about as great a variety as possible, and with that, 

 the highest possible prospect for the required quantity 

 of superior specimens. At the moment when the produc- 

 tion of the sexual cells begins, in such enormous numbers, 

 it also finds the best opportunity for fulfilling its task. 



Thus, sexual reproduction has only a subordinate sig- 

 nificance for the children, while for the grandchildren it 

 is of the utmost importance, because only for them does 

 the urn mix up all its lots. 



The same laws that govern normal fertilization, are, 

 of course, valid for hybrids also. There cannot be special 

 biological laws for them, because they are only derived 

 phenomena, deviations from the normal. Now the ques- 

 tion is, to which results, departing from the rule, will the 

 common laws lead in these special cases. And with this 



