CONCLUSIONS 277 



further investigation, since it should lead to a better 

 understanding of bodily function, both in health and 

 disease. This seems all the more certain, since, as we 

 have shown, a number of pathological conditions of 

 admittedly obscure origin can be easily induced by 

 a series of sublethal injections of homologous cytost. 



These effects of cytost on the intact animal are but 

 the expression of the integrated effects upon the indi- 

 vidual tissue cells. This follows from our experi- 

 ments on tissue cultures and upon the growth of para- 

 mecia, where, it may be recalled, small quantities of 

 homologous cytost were found to exert a distinctly 

 stimulating effect upon the cells, while the character- 

 istic toxic action of cytost became manifest if its con- 

 centration in the media was too high. 



These two actions of cytost may seem paradoxical, 

 but since they are attested to by the results of literally 

 hundreds of experiments, they cannot be questioned. 



Indeed, nature seems to have endowed all biological 

 systems with apparently paradoxical reactions to 

 baffle the investigator. Thus, the life of the majority 

 of animal cells is adapted to a definite partial pres- 

 sure of oygen ; oxygen tensions less than or greater than 

 the optimum lead to anomalous activity frequently 

 resulting in death. The same is true of the ionic bal- 

 ance of salts in the fluid media surrounding such cells. 



It is not illogical, therefore, to postulate that a cer- 

 tain optimal concentration of cytost is compatible 

 with the normal functioning of cells, whereas when 

 this optimum is exceeded in one direction or the other 

 anomalous behavior results. When such anomalous 

 behavior becomes excessive, a pathological condition 

 ensues. 



