IN THE HIGHER ANIMALS. 169 



and necessary for the completion of the development. The 

 female egg — or that which receives fertilization from the 

 drone — is in possession of an added force, which enables it, 

 in the presence of suitable food, to acquire unto itself the 

 forces necessary for development into a worker, or even into 

 a queen-bee. 



In the higher animals we find the process of reproduction 

 by generation universal. In other words, so great is the 

 complexity of their environment, and so complex is their 

 structure for meeting the changes brought about by this very 

 complexity, that we find the various parts and organs of the 

 body highly specialized. As a resultant therefrom, we observe 

 but a limited repair even to the tissues of the body, and this 

 repair far more common in the womb and during childhood 

 than in old age. The generative organs are highly special- 

 ized, as they are fitted through long-continued inheritance, 

 with variation arising from the persistence of past and present 

 impressions, for the tran?missal of those qualities with which 

 they have or may be impressed. The force inherent, how- 

 ever, is insufficient, or not of the right quality, of itself, in the 

 male or female cell, to advance further development than the 

 stage in which we find it. By the union of the two forces 

 we have a sufficiency to overcome the difficulties, and a further 

 development may take place. 



This statement is illustrated by the experiments of Gartner, 

 who, after making successive trials on a malva with more and 

 more pollen grains, found that a few grains of pollen did not 

 fertilize a single seed ; that enough pollen might be added to 

 form a few seeds of small size, while a sufficiency would pro- 

 duce the full development. Naudin followed the same line of 

 investigation with the mirabilis, in which the pollen grains 

 are large and the ovarium contains but a single ovule. A 

 flower was fertilized by three grains and succeeded perfectly ; 

 twelve flowers by two grains, and seventeen flowers by a 

 single grain, and of these but one flower in each lot perfected 

 its seed ; and it is worthy of notice that the plants produced 

 by these two seeds never attained their proper dimensions, 

 and bore flowers of remarkably small size.* 



In the ingenious experiments of Mr. Newport upon ova of 

 amphibia, it is shown that the contact of a single spermato- 



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