FURTHtR RlISl-ARCMES IN DlSHASF.S OF Pl.ANTS ^11 



nothint; w.is obtained arul witli the low-boiling hydrocarbons only mild 

 resin(ts\vhich first appeared after many days. On the contrary with a pro- 

 duct which distills over above 300'C. and is soluble in benzol, astonishing 

 results were obtained. With such a distillate they stale they were able to 

 produce skin cancers on mice in four months' time in 100 per cent of the 

 cases (number not stated nor strains or age of mice employed). Their 

 technique was the same as that used by Yamagiwa. . . . 



This docs not imply that Smith was first, or among the first, 

 to realize the value of, and recommend to cancer research workers, 

 the use of phenols, hydrocarbons, and various chemicals for tumor 

 inductic^i. He was, however, among the first, if not the first, of 

 the students of crown gall and cancer, to recognize the value of, 

 and apply, chemicals and chemical influences in experimentally 

 inducing tumors in plants. Utilizing techniques of his own making 

 and techniques devised by others to study tumors of animals and 

 man, he obtained in plants, through less than killing doses, types 

 of cell-growth varying between what he regarded as hyperplasias 

 and hypertrophies or a combination of the two. He produced 

 overgrowths in plafts with at least a half-dozen and more sub- 

 stances which readily pass through protoplasmic membranes, each 

 of which are products of Bacterium ttimejaciens: ammonia, amines, 

 aldehyd, alcohol, acetone, acetic acid, formic acid, and carbonic 

 acid ( ?) . Many more effective compounds have been reported since 

 his years, each active in gall production in plants. During his last 

 years this subject became one of his special research interests. 



