358 THE SELF-FERTILIZATION OF PLANTS. 



ting against his "law," he speaks as follows (p. 116, 

 Vol. ii, Animals and Plants, &c.) : 



"The Leersia oryzoids produces minute, enclosed 

 flowers which cannot possibly be crossed, and these alone, 

 to the exclusion of the ordinary flawers, have as yet been 

 known to yield seed. (/) A few additional and analo- 

 gous cases could be advanced. But, these facts do not 

 make me doubt, that it is a general law of nature, that 

 the individuals of the same species occasionally inter- 

 cross, and that some great advantage is derived from 

 this act." 



Some great good is derived from the intercrossing 

 of individuals of the same species, because they each 

 have, in them, some positive point of structure, which 

 is needed in every individual of the given species. In 

 presence of facts, like these enclosed flowers, preclud- 

 ing the possibility of crossing, Darwin trims, some- 

 what, his "law." As he states his "law," elsewhere, 

 it is an absolute necessity, that individuals of the same 

 species should cross. Here, however, in the quotation 

 above, he states it, in a manner which is very little de- 

 fective. 



" Some great advantage " is, undoubtedly, often " de- 

 rived from this act" of Crossing. But, it is not a great 

 "law of nature." It is due to structural defects in 

 either parent being supplied by positive differences in 

 the other parent. 



When individuals of a species are disproportionately 

 developed, a " great advantage is," without doubt, " de- 

 rived from the act'-' of crossing. But, there is no 

 " law of nature," requiring a cross. An individual, and 

 its descendants, which have, each, all of the positive 



