GEMMATION AND GENERATION". 327 



Generation. " The young Hydra from the bud is iden- 

 tical in organic structure and character with tliat which 

 comes from the ovum ; and when the effects of organic 

 development are the same, their efficient causes cannot 

 be 'altogether distinct;' only the non-essential acces- 

 sories of the process may be the subject of variation." 

 And Dr Alexander Harvey reminds us on this point, 

 that " things that are equal to the same, are equal to 

 one another;" so that if the product of the bud and the 

 product of the seed be in all respects identical, there 

 must necessarily be an identity between the seed and 

 bud.* The potato-seed and the potato-bud both ger- 

 minate apart from the parent plant, and both give rise 

 to organisms in all respects identical. " What, let me 

 ask, is included in the statement that the bud can evolve 

 a perfect and complete plant — that it can evolve the 

 flower and the seed ? This : that it must contain ivithin 

 itself the two kinds of cell regarded as essential to 

 the constitution of the seed, — as forming the essential 

 characteristics of the seed, namely the ' sperm-cell,' and 

 the ' germ-cell.' " -f I do not accept the current idea 

 respecting the germ-cell and sperm-cell as essentially 

 necessary to the seed, and Dr Harvey himself seems to 

 have relinquished the idea in his more recent work ; but 

 in both works he has established the essential identity 

 of bud and seed, and consequently of Gemmation and 

 Generation. Wolff Ions; ao;o taught that the bud was 



* See his two interesting works, Trees and their Nature, 1856 ; and 

 The Identity between the Bud and tJce Seed, 1857. 

 f Harvey : Treesi and their Nature,^. 185. 



