166 CHARLES DARWIN. 



unimpregnated ovule is already alive, and continues 

 for a considerable time alive." 



It is very remarkable to note how largely Pro- 

 fessor WeismanfTs conclusions on this subject were 

 anticipated by this part of Darwin's work. 



Graft hybrids. The probability that a graft may 

 alter the character of the stock to which it is united, 

 so that hybrid buds might be formed by budding or 

 grafting the tissues of distinct varieties or species, 

 would, if it became a certainty, prove the essential 

 identity of sexual and asexual reproduction : " for the 

 power of combining in the offspring the characters 

 of both parents is the most striking of all the 

 functions of sexual generation." 



Direct action of the male element on the female. 

 Pollen from another species is known to affect the 

 mother-plant in certain cases. Thus pollen from the 

 lemon has caused stripes of lemon-peel in the fruit 

 of the orange; the peel is, of course, formed by 

 the mother -plant, and is quite different from 

 the part which the male element is adapted to 

 affect viz. the ovule. Similar cases are known 

 among animals, as in the celebrated example of 

 Lord Morton's mare. 



Development. The changes by which the embryo 

 reaches maturity differ immensely, even within the 

 limits of the same compact group. Forms which 

 closely resemble each other in the mature state, and 

 are intimately related to each other, such as the vari- 

 ous species of lobster and crayfish, etc., pass through 



