4 Faraday, Biological Aspect of Cancer. 



will be liberated as germs of independent communities or 

 growths through the dissolution of the mycelium, which, 

 like summ.er annuals, having surrendered its vital force to 

 its offspring, crumbles away. 



Now, may we not carry the thought a little further and 

 assume that both possibilities are inherent in the original 

 cell or living molecule ? The potentiality of variation, 

 division of labour, and co-operation must be assumed as 

 existent in every cell, otherwise how could cells ever have 

 become highly organised communities? Moreover, ex- 

 perience has shown us, what in any case we should have 

 been obliged to infer as the only possible explanation, 

 that the development of one or the other tendency must 

 be determined by the environment, or the conditions under 

 which the particular life has to be carried on. Thus the 

 character of the season will determine whether a tree will 

 make wood or flowers, whether the wheat plant will make 

 much straw or a full ear. Place a leguminous seed or 

 tuber in the darkened portion of a cellar, it will send forth 

 long shoots of mycelium until it obtains the direct contact 

 of the solar rays, when the differentiations which result in 

 inflorescence will begin. And whether anthrax will pro- 

 duce spores, or not, has been said by various observers to 

 depend on the presence or absence of free oxygen. 



I have spoken of reproduction by eggs as a general 

 expression for reproduction by spores, seeds, or eggs as 

 distinct from reproduction by mere scissiparity. But, 

 technically, we apply the term spore to what may be 

 spoken of as the seeds or eggs of the lower forms of life; in 

 other words of the less highly differentiated communities of 

 cells. These may be regarded as representing an inter- 

 mediate stage between the simple cell or living molecule 

 and the highly complex organism, say man, in which what 

 I may call economic differentiation has attained its 



