VALUE OF THE ATTRACTION-SPHERE. 161 



as important functions in relation to hereditary phenomena 

 as the nuclei themselves. In order, however, to really claim 

 this for the spheres it would be necessary to find at least 

 as strong evidence for their universal bi-sexual origin and 

 fusion during fertilisation as we have in the case of the 

 nuclear elements. Yet it is sufficiently apparent that 

 nothing of the kind is forthcoming, that it is impossible to 

 formulate any rule having the faintest pretence to be general 

 respecting the uni-sexual or bi-sexual origin of the spheres ; 

 and we are equally baffled by the want of unanimity in re- 

 corded observations when we try to determine whether the 

 spheres in their origin are always derivatives of pre-existing 

 spheres. Of the two alternative answers to the first 

 question, however, one must be true. Either the spheres 

 have an altogether mixed origin, and can arise indifferently 

 from the male or female, or be evolved in the egg at the 

 time of fertilisation, and are ipso facto excluded from any 

 hereditary value whatever, or those observations which 

 tend to show that they originate in this way are incomplete, 

 and with more extended knowledge their bi-sexual nature and 

 fusion will be established throughout. Nor should it be for- 

 gotten that the evidence which militates against this bi-sexual 

 origin is of one kind only. It consists of the non-forth- 

 coming of one or other of the figures of that " Marche du 

 quadrille," as Fol originally described it ; and it appears 

 consequently at first sight to be negative. 



With respect to the persistent or evolved nature of the 

 spheres, it will, moreover, be obvious that these structures 

 may be persistent, although arising from one parent only ; 

 and the only direct evidence against their persistence in this 

 sense is that which supports the view that they are evolved 

 de novo in the egg, and is at present very slender. Undoubt- 

 edly attraction-spheres are brought in by the spermatozoa 

 in some species of animals, whatever may be the case in 

 plants, while bodies answering to them are incorporated 

 with the male element during spermatogenesis or its equiva- 

 lent in others. Evidence which is really positive has greater 

 weight than any amount of that which is merely negative, 



and on the strength of this, probability seems to set towards 



ii 



