Manchester Memoirs, Vol. x/m. (iSgg), No. l*^. g 



I would venture to express the view in a broad 

 generalisation : — Free oxygen and sunlight are favourable 

 to phanerogamic development, their absence to crypto- 

 gamic life. If we go back in geological history we find 

 that when the world was probably largely enveloped in 

 carbonic acid gas and the vapours of steaming seas, the 

 great filicin^, equisitacese and lycopodinse, and the enor- 

 mous lizards and other sluggish forms of life prevailed. 

 Their huge bodies testified to conditions favourable to the 

 growth of mere (relatively) undifferentiated mycelium, 

 rather than to the evolution of the complex nerve tissues 

 and highly elaborated system of well-ordered canal irri- 

 gation by means of sap and blood vessels characteristic 

 of the higher plants and animals. It does not seem 

 entirely fanciful to associate the prevalence of the 

 degenerative processes of cancer along river valleys with 

 this generalisation. There appears also to be a striking 

 relation between cancer and tuberculosis. Dr. Thorburn, 

 for instance, has found statistically that there is frequently 

 a family history of tuberculosis in cases of cancer. 

 Tuberculosis we know to be associated with deficient 

 light and ventilation, and the mists or vapours of river 

 valleys suggest less efficient oxygenization of the bloodthan 

 takes place in dryer localities. However that may be, such 

 deficient oxygenization does not seem an insufficient cause 

 to account for cryptogamic arrest, or reversion, on the 

 part of the cells or micro-cocci of which the human being 

 is built. In the case of cancer, a bruise, or any inter- 

 ference with the efficient oxygenization of the part by the 

 blood stream may initiate the local growth. But if we 

 assume imperfectly oxygenized blood throughout the body, 

 the escaping cell starting from the original centre in which 

 its malignant vigour has been nurtured, lodges amidst 

 tissues which are themselves being imperfectly renewed 



