148 An Examination of Weismannism. 



tially immortal, while the multicellular have acquired 

 mortality for certain adaptive reasons. 



But now. with the exception of No. 4, all these 

 positions have been abandoned. For. chiefly on 

 account of the beautiful researches of Maupas, Weis- 

 mann has come to perceive that no real distinction 

 can be drawn between an act of sexual union in 

 the multicellular organisms, and an act of conjuga- 

 tion in the unicellular. Amphimixis, therefore, is 

 now held by him to occur equally in both these 

 divisions of organic nature, with the consequence 

 that the Protozoa and Protophyta owe their indi- 

 vidual variations, and therefore the origin of their 

 innumerable species, as exclusively to the action 

 of natural selection as is the case with the Metazoa 

 and Metaphyta. In fact, the term " amphimixis " has 

 been coined in express relation to these very points. 



It will be seen, however, that this important change 

 of view merely postpones the question as to the 

 origin of amphimixis, if the object of this process be 

 that which YVeismann supposes — -viz., the providing of 

 material in the way of congenital variations on which 

 natural selection can act. Therefore he is obliged 

 to assume that there now are. or once have been, 

 organisms of a less organized character than even the 

 lowest of the unicellular forms — organsims, that is 

 to say, which possess no nucleus, but are wholly 

 composed of undifferentiated bioplasm. These most 

 primitive organisms it must have been that were not 

 subject to any process of natural selection, but, in virtue 

 of an exclusive action of the Lamarckian factors upon 

 their protoplasmic substance, gave rise to individual 

 variations which subsequently gave rise to a unicellular 



