individuals with a more or less useless organ will result in 

 the production of progeny that is below the general level 

 of efficiency, and the organ will appear degenerate. 



General mixing of this nature Weismann called Pan- 

 mixia. 



Objections to Weismann' s Theory. — The main object- 

 tions come from botanists who find in plants the common 

 phenomenon of regeneration of the whole organism from 

 parts which do not contain the reproductive organs. In 

 plants like begonia and marchantia the vegetative cell must 

 contain the same initials as the germ cell, and there is no 

 difference in the hereditary characters. 



1. The hereditary characters are not confined to the 

 germ-cells, e.g., in plant regeneration by cuttings, 

 grafts, etc. Weismann supposes that in the higher 

 plants germ plasm is contained in a great many 

 cells, in a latent state, and only becomes active 

 according to the influences bearing on it. 



2. The chromosomes are not definite organs of the 

 cells, as they disappear in the anaphase stage of 

 cell division (see Jost). 



3. The chromosomes do not constitute the whole of 

 the nucleus, and perhaps the hereditary capacity 

 lies in some other nuclear substance (See Jost). 

 "In Lilium it has been demonstrated that when 

 fusion occurs there is no cytoplasm whatever in- 

 vesting the male nucleus." 



4. In certain hybrids, i.e., Cytisus adami (C. laburnum 

 X C. purpureus) initials are sometimes lost (see 

 Jost and Baur). Cytisus adami is a sterile hybrid 

 and has most organs intermediate in character. 

 It splits in a vegetative way, reverting to its 

 parents. 



5. A possibility of migration of idioplasm from one 

 cell to another. 



6. The germ plasm must be preserved along with the 

 soma plasm in plants when not in flower, else where 

 does the germ plasm reside in the sporophyte? 



7. The germ plasm in the sex elements of flowers may 

 be directly exposed to external influences (Hen- 

 slow, The Origin of Floral Structures). 



8. The non-transmissibility of acquired characters is 

 not a corollary of the continuity of the germ plasm. 



9. Asexually multiplied plants show variations and 

 these variations may be transmitted from genera- 

 tion to generation (Bailey). 



56 



