Chap. XXVIL OF PANGENESIS. 'SSI 



that at least in a large number of cases the power of re-growth 

 is a localised faculty, acquired for the sake of repairing special 

 injuries to which each particular creature is liable ; and in 

 the case of buds or fissiparous generation, for the sake of 

 quickly multiplying the organism at a period of life when it 

 can be supported in large numbers. These considerations 

 lead us to believe that in all such cases a stock of nascent cells 

 or of partially developed gemmules are retained for this 

 special purpose either locally or throughout the body, ready 

 to combine with the gemmules derived from the cells which 

 come next in due succession. If this be admitted we have a 

 sufficient answer to the above two objections. Anyhow, pan- 

 genesis seems to throw a considerable amount of light on the 

 wonderful power of re-growth. 



It follows, also, from the view just given, that the sexual 

 elements differ from buds in not including nascent cells or 

 gemmules in a somewhat advanced stage of development, so 

 that only the gemmules belonging to the earliest stages are 

 first developed. As young animals and those which stand 

 low in the scale generally have a much greater capacity for 

 re-growth than older and higher animals, it would also appear 

 that they retain cells in a nascent state, or partially developed 

 gemmules, more readily than do animals which have already 

 passed through a long series of developmental changes. 1 

 may here add that although ovules can be detected in most 

 or all female animals at an extremely early age, there is no 

 reason to doubt that gemmules derived from parts modified 

 during maturity can pass into the ovules. 



With respect to hybridism, pangenesis agrees well with 

 most of the ascertained facts. We must believe, as pre- 

 viously shown, that several gemmules are requisite for 

 the development of each cell or unit. But from the occur- 

 rence of parthenogenesis, more especially from those cases 

 in which an embryo is only partially formed, we may infer 

 that the female element generally includes gemmules in nearly 

 sufficient number for independent development, so that when 

 united with the male element the gemmules are superabun- 

 dant. Now, when two species or races are crossed reciprocally, 

 the offspring do not commonly differ, and this shows that the 



