METHODS OF REPRODUCTION. 167 



received from the sperm. This is the case with some butter- 

 flies, and most notably in the case of the queen-bee, whose 

 eggs, produced under circumstances that forbid the suspicion 

 of fecundation, can and do advance towards maturity and 

 develop into the completed insect — the drone. In this instance 

 we seem to have the gemmiferous method of reproduction in 

 quite highly-constituted insects, whose continued existence is 

 dependent on the oviparous or true generative process. 



In reproduction by division, we seem to have a tendency 

 towards a weakening of the germinal capacity, as is indicated 

 by the consideration of those lower forms of vitality in which 

 the process of nutrition and reproduction are more clearly 

 dependent on each other. Thus, limitations of growth and 

 arising through age indicate a decrease of germinal energy in 

 the reproduction of cells in the tissues, as also does the con- 

 verse fact that repair of injuries takes place with far greater 

 completeness and energy in the young than in the old. In 

 organisms that multiply by the fissiparous and gemmiferous 

 method, there is usually, if not universally, some provision 

 made for the occasional formation of new beings by the process 

 of fecundation, or of union with distinct cells. 



In the plant and in the simple animal life we find a homo- 

 geneity of structure, which has but comparatively few special- 

 ized functions for its cells. Like those parts of the tissues of 

 higher animals which readily undergo repair, these cells are 

 formed mostly through nutritive repetition, and the forces 

 which regulate development appear quite simple in character 

 and evenly distributed throughout the whole cell-structure. 

 Thus the polype may be divided and subdivided, and each 

 portion will develop into a new polype. The twig removed 

 from the plant may form rcots and develop itself into an 

 individual plant like the parent stock. 



It will be seen that the functions of nutrition and repro- 

 duction are, in one sense, allied. They are both dependent 

 for their origination and for the carrying out of their functions 

 upon a force derived external to themselves. In the fissipa- 

 rous method of reproduction we recognize the process by 

 which both the cells of animal tissues may be formed and 

 the origination of indepen 'ent individuals among the lower 

 organisms. In the gemmiparous method we have an instance 



