Manchester Memoirs, Vol. xliii. (1899), ^'^- l^* 5 



maximum development. May we not further suppose 

 that each stage is represented in the higher organism and 

 retains all its original and acquired potentialities ? That 

 the cells of the higher organisms retain their power of mere 

 scissiparity we know, for it is by such reproduction that 

 the plant or the animal grows ; may not particular tissues 

 corresponding to the higher cryptogamic stage of plants, 

 above the thallophyta — say the ferns — have a tendency 

 under given conditions to revert to independent spore pro- 

 duction with the resultant decay of the parent mycelium ? 

 This would be as though the leaves of a phanerogam 

 forgot their duty to the community represented by 

 the whole plant and began to produce spores ; or as 

 if the workers in a hive began to lay eggs instead of 

 leaving that duty to the queen bee. Some of the 

 phenomena of scarlet fever might perhaps be accounted 

 for as due to some condition which awoke in the skin- 

 tissue, the potentiality of independent spore formation. 

 The initial stages of cancer, and of the various forms of 

 epithelial proliferations may under this view be con- 

 ceivably due to some change of environment, which 

 setting free and even stimulating the power of independent 

 multiplication by mere scissiparity in a particular region 

 or in one or more cells, at the same time arrests the 

 tendency to differentiation in the service of the community 

 or of the general organism. In that case the cancer, in 

 its initial stages, would be a case of arrested development, 

 or of reproduction not proceeding beyond the original 

 mere cell-formation stage, the result being a local growth 

 of an independent, or non-cooperative, character. 



Cancer has been defined as epithelial proliferation 

 with an invading tendency, and this invading tendency 

 seems to be truly parasitical, as the invading cells appear 

 to destroy, or absorb, or replace the normal tissues around. 



