SEXUAL REPRODUCTION I45 



The early researches of Kolreuter (i 761) gave a firm basis to the study of 

 hybridization among plants. The comparative easiness of experiment has 

 advanced the botanical side of the subject to far greater certainty than the 

 zoological conclusions can pretend to. Among plants, as we should expect 

 from their greater vegetativeness, the fertility of hybrids seems frequently 

 established. Knight, Gartner, Herbert, Wichura, and others, have brought 

 together a great number of reliable observations, and the whole subject has 

 been admirably discussed by Nageli. For a copious resume of the general 

 results, for the most part after Nageli, the student may be referred to chap. vi. 

 of Sachs' Textbook of Botany, while Wallace's "Darwinism" [No. 115 and No. 

 116 of The Humboldt Library'] should be consulted for its rediscussion of 

 hybridization in animals. 



