580 Third European Journey 



was advanced a theory of cell and tissue heaping and stagnation 

 as a cause of cancer. This theory Smith discussed with Warburg's. 



Since 1917 in his address, " Mechanism of Overgrowth in 

 Plants," ' Smith had urged that in tumor etiology much might be 

 learned from following a line of inquiry represented by Dr. 

 Bernhard Fischer's paper (1906) on overgrowths of epithelium 

 due to the injection of scarlet red and indophenol into rabbit's 

 ears. He said, " Fischer's paper in particular pointed the way 

 clearly toward the solution of the cancer problem, but it was 

 received very coldly and he became discouraged, and no one else 

 took up the suggested clue." The point to remember was not 

 Fischer's discouragement when the " invading epithelial cells sub- 

 sequently ceased to grow, with disappearance of the stimulus, and 

 were finally absorbed." Smith stressed that " if specialists had 

 then assumed that quite other substances than scarlet red and 

 indophenol can cause overgrowths, as we now know, and that 

 some of the substances may be the products of tumor-producing 

 parasites, as also we now know, how suddenly luminous the whole 

 subject would have become and what an incentive it would have 

 given, and still gives, to further research! " 



When, therefore, five and one-half years later. Smith examined 

 the facts concerning experimental cancers reported from injec- 

 tions with anilin compounds — "Anilin-Dye Cancers," ^ he called 

 them — he explained more about Fischer's " remarkable results . . . 

 obtained by injecting rabbits' ears with olive oil saturated with 

 scarlet red." Describing why subsequent experiments, whichj 

 followed the "' good deal of interest " created by Fischer's pub- 

 lication, failed, he suggested, "Here apparently, as in case of 

 the coal-tar treatments, the failures were due to lack of persis- 

 tency on the part of the experimenters, since in 1918 Yamagiwa 

 and Ohno reported success with scarlet red dissolved in olive oil 

 when injected into the wall of the ovary in hens (Gann, Bd. XII, 



^ op. cit., AAA. 



"Twentieth century advances in cancer research, op. cit., 315. By 1945 the sub- 

 stances of known tumor-inducing effectiveness, chemical, mechanical, physical, etc., 

 were believed to be " at last accounting . . . more than 290 " in number. See Peyton 

 Rous " Concerning the Cancer Problem," Ajnerican Scientist 34: 329-358, at 336, 

 1946'. This paper, presented that year in the Sigma Xi national lectureships, is 

 especially valuable for its discussion of "' tumor-producing viruses," and mentioned 

 among other carcmogenic agents the hydrocarbons and "' fat soluble dyes Sudan III 

 and Scharlach R." 



