INFLUENCE OF NUTRITION ON POISONS 389 



the influence of the diet on the growth of neoplasms. As for the 

 first factor, we can not take it up in such great detail as we should 

 like to, unfortunately, since it does not fall in the sphere of this book. 

 We were one of the first to point out this possibility, but we must 

 admit that aside from the influence of the diet on the growth of 

 experimental tumors and a possible chemical cause of certain neo- 

 plasms, such as the chicken sarcoma of Rous and analogous tumors, 

 we have no firm basis for our conception. If we (1555) choose this 

 line of thought in preference to the other known ones, it is because 

 cancer research, in the hands of pathologists, has" yielded very little 

 tangible results. Some of the known pathologists, like Ewing (1556) 

 and Leo Loeb (1557) were inclined to a similar view at one time. 

 Certain experimental papers like those of Calkins (1558), who 

 reported on the stimulation of protozoa (Didinium nasutum) by 

 tumor extracts, may be interpreted in the above manner; still, it is 

 possible that it may be associated with the influence of a dietary or 

 vitamine addition. The various investigations dealing with the 

 effect of pregnancy on the growth of neoplasms may also be inter- 

 preted from the viewpoint of the chemical theory. From these 

 investigations, we may see that the embryo contains a substance 

 that stimulates the growth of neoplasms. The growing embryo, 

 however, according to v. Graff (1559) and Slye (1560), needs this 

 substance for its own growth, thereby inhibiting considerably the 

 tumor growth. 



That the diet exerts some influence on tumor growth, was suspected 

 by Ehrlich in his athreptic theory. This theory was tested experi- 

 mentally by Jansen (1561) and Haaland (1562) who established the 

 inhibiting influence of under-feeding. Similar experiments were 

 also undertaken by Cramer and Pringle (1563), Rous (1564) and 

 v. Jaworski (1565). The latter believed that under-feeding inhibits 

 the growth of tumors. In his opinion, carcinomas were an exception 

 since, under such conditions, they grew even more rapidly. The 

 dietetic aspect of cancer research was stimulated by vitamine studies. 

 Sweet, Corson-White and Saxon (1566), in their rat and mouse experi- 

 ments, used the Osborne-Mendel diet and saw that the growth of 

 tumors on a vitamine-poor diet was markedly arrested. In quick 

 succession, there appeared papers on the same subject by Hopkins 

 (1567), Centanni (1568), Rous (1569), Drummond (1570) (this work 

 being very exhaustive), Benedict and Rahe (1571) and Sugiura and 



