108 THE ACTION OF THE LIVING CELL 



strated that the movements of the body fluids in the 

 capillaries is entirely dependent upon the contraction 

 of the surrounding muscles, and today physiologists 

 are generally agreed that the venous return to the 

 heart is dependent upon this factor. Hence, during 

 enforced quiescence there must be some degree of 

 stagnation of blood in the finer vessels, which prevents 

 both an adequate nutritive supply and the removal of 

 toxic waste products. From the preceding discussion 

 it should be obvious that the former will cause an 

 increased liberation of cytost, while the impairment 

 of circulation must necessarily bring about the ex- 

 posure of the tissue cells to higher concentrations of 

 the toxin than would otherwise be the case. 



In consequence, it is not surprising that the tissue 

 degenerations and pathological findings in animals 

 whose quiescence has been enforced should closely 

 parallel those induced by the frequent injection of 

 sublethal quantities of cytost. 



Of all the results obtained in the writer's experi- 

 ments, the following are the most interesting (Turck, 

 1921b) : A pair of two months old kittens from the 

 same litter were injected subcutaneously with like 

 quantities of the same cytost extract. One, which we 

 may call "A," was injected once a week; while the 

 other, "B," received the injections daily or every other 

 day. Much to our amazement, "A" gained in size 

 and weight more rapidly than the other, untreated kit- 

 tens of the same litter, whereas "B" ceased to grow, 

 and suffered a progressive decline in weight. This 

 was accompanied by senile changes, until, after two 

 months of such treatment, the kitten (then four months 

 old) appeared as a decrepit old animal, 



