1858.] the. Phenomena oj Gemmation. 537 



Among the latter, the speaker cited the wonderful circum- 

 stonces attending the production of the drones among bees, as 

 described by Von Siebold ; and he drew attention to the plant 

 upon the table, Cwlohogyne ilicifolia, a female euphorbiaceous 

 shrub, the male flowers of which have never yet been seen, and 

 which nevertheless, for the last twenty years, has produced its 

 annual crop of fertile seeds in Kew Gardens. 



Not only can we find numerous cases of agamogenesis similar 

 to that exhibited by Aphis in the animal and vegetable worlds, but 

 if we look closely into the matter, agamogenesis is found to pass by 

 insensible gradations into the commonest phenomena of life. All 

 life, in fact, is accompanied by incessant growth and metamorphosis ; 

 and every animal and plant above the very lowest attains its adult 

 form by the development of a succession of buds. When these 

 buds remain connected together, we do not distinguish the process 

 as anything remarkable ; when on the other hand, they become 

 detached and live independently, we have agamogenesis. Why 

 some buds assume one form and some another, why some remain 

 attached and some become detached, we know not. Such phe- 

 nomena are for the present the ultimate facts of biological science ; 

 and as we cannot understand the simplest among them, it would 

 seem useless, as yet, to seek for an explanation of the more complex. 



Nevertheless, an explanation of agamogenesis in the Aphis and 

 in like cases has been offered. It has been supposed to depend 

 upon " the retention unchanged of some part of the primitive 

 germ-mass ;" this germ-mass being imagined to be the seat of a 

 peculiar force, by virtue of which it gives rise to independent 

 organisms. 



There are however two objections to this hypothesis : ift the first 

 place, it is at direct variance with the results of observation ; in the 

 second, even if it were true, it does not help us to understand the 

 phenomena. With regard to the former point, the hypothesis pro- 

 fesses to be based upon only two direct observations, one upon 

 Aphis, the other upon Hydra ; and both these observations are 

 erroneous, for in neither of these animals is iany portion of the 

 primitive germ-mass retained, as it is said to be, in that part which 

 is the seat of agamogenesis. 



But suppose the fact to be as the hypothesis requires ; imagine 

 that the terminal chamber of the pseudovarium is full of nothing 

 but " unaltered germ-cells ;" how does this explain the phenomena ? 

 Structures having quite as great claim to the title of " unaltered 

 germ cells '* lie in the extremities of the acini of the secreting 

 glands, in the sub-epidermal tissues and elsewhere ; why do not 

 they give rise to young ? Cells, less changed than those of the 

 pseudovarium of Aphis, and more directly derived from the primi- 

 tive germ-mass, underlie the epidermis of one's hand ; nevertheless, 

 no one feels any alarm lest a nascent wart should turn out to be 

 an heir. 



