PRESIDENT'S ADDRESS. 15 



solution, goes to shew that every cell in all the tissues of a 

 multicellular organism throws off germs or gemmules, which 

 multiply by self-division, and after circulating through the whole 

 body are collected from all parts of the system in the condition of 

 cell-seeds, which have a strong affinity for each other. These 

 constitute the generative ova and spermatozoa, the fusion of which 

 produces a new organism. A large number failing to develop, are 

 transmitted in a dormant state to future generations to be sub- 

 sequently developed. These are not thrown off until the organism 

 is in an adult state. Doctor Weissman, on the other hand, 

 supposes that in multicellular organisms some cells, which he 

 terms somatic cells, are specially fitted to provide for nutrition, 

 while others germ-cells perform the work of production. 

 These he considers are transmitted without break of continuity 

 from one generation to the next, and do not differentiate until 

 late in embryo growth, ultimately attaining a highly specialised 

 character. 



The germ-plasms, which originated in the unicellular organisms, 

 are carried on in the multicellular in continuity from generation to 

 generation. On the occasion of the fusion of two germ-plasms a 

 new organism is formed and a portion of it placed aside in the 

 gemmule-cells to secure that continuity. This fusion must bring 

 different proportions of different elements together in each 

 generation ; but a point requiring explanation is how the several 

 varieties in the germ-cells commenced in order to make generic and 

 specific differences. The two theories of Pangenesis and heredity 

 are extremes of several intermediates, differing more or less from 

 both. For my part it appears to me the problem must remain 

 among the hidden arcana of Nature's mysteries. 



