CYTOST IN THE PLANT WORLD 255 



potatoes, leads to a noticeable increase in the rate of 

 germination. 



If it be conceded that such injuries lead to the liber- 

 ation of cytost, we may draw a somewhat crude anal- 

 ogy between the acceleration of germination and the 

 beneficial effects of homologous cytost upon the breed- 

 ing of laboratory animals. It would be exceedingly 

 interesting to study the effects of cytost extracts pre- 

 pared from potatoes upon the growth of the latter. 

 In this connection it may not be amiss to suggest that 

 the current practice of plowing under those portions 

 of plants which are of no economic importance may 

 possess benefits aside from the return of nitrogen and 

 mineral salts to the soil. Conceivably the autolysis of 

 such plant material within the soil may lead to the 

 accumulation of a certain amount of cytost which is 

 actually beneficial to the growth of succeeding gener- 

 ations of plants. 



Before leaving the topic of trauma in plants, it may 

 be worth while to note that Buenning (1926), in an 

 investigation of the effects of mechanical irritation on 

 Aelium ascolonicum, has observed that such injury 

 and excessive heat both lead to the liberation from 

 the injured tissues of some substance which is capa- 

 ble of affecting neighboring cells, leading to coagula- 

 tion and increased permeability. This is in harmony 

 with the author's observation that similar effects fol- 

 low the exposure of animal cells to the abnormal con- 

 centrations of homologous cytost. 



As a result of his experiments, Buenning suggests 

 that the substance responsible for the histological 

 changes which he observed may be inorganic salts 

 freshly liberated from the plant tissues as a result of 



