Resistance of Mice to the Growth of Cancer. 187 



anti-toxic or anti-cellular action, but we are far from denying the possibility 

 that such an action may be obtained. 



The phagocytosis of formed cellular elements plays an important rdle in 

 inducing resistance ; serum is impotent to produce resistance, blood corpuscles 

 do so. The energetic phago^tosis which accompanies the spontaneous 

 absorption of transplanted tumours, and which occurs in absorption after 

 exposure to radium, speaks strongly for the conclusion that the processes are 

 the same in kind when blood or tumour cells, being absorbed, produce 

 resistance. But we are as yet unable to determine the extent to which 

 agencies directed against the tumour cells themselves may assist in 

 determining their early death in protected animals. Other experiments 

 still in progress may be expected to clear up the relative importance of the 

 parts played by the hypothetical inhibition of the specific stroma reaction, or 

 of an equally hypothetical direct lethal action on the tumour cells. 



VOL. LXXIX. — B. 



