RcsoARcn ON Plant Tumors 471 



iniprDvcincnts in tluii;iu)sis and dcinuiistialcd the organism's 

 connection with general paresis and locomotor ataxia/ In 1909- 

 1910 Paul Ehrlich's discovery of the organic arsenic compound, 

 salvarsan or " 6O6," had proved remedial, at least in part.'"* 

 Smith knew of other recent medical research triumphs. Drs. 

 Simon Flexner and Lewis, at the Rockefeller Institute, in 1909," 

 " by intracranial inoculation of tissue from diseased spinal cords 

 [had] produced infantile paralysis in monkeys and transmitted 

 it from one monkey to another through a long series. Eighty-one 

 monkeys were infected with the virus and the average incubation 

 period was 9-82 days." New discoveries have been made since 

 this list was prepared in 1926 by Smith. By 1913 Flexner and 

 NofTuchi had " cultivated from the brains of children dead of 

 infantile paralysis a very minute, filter-passing, coccus-like or- 

 ganism, about 0.2/i in diameter, with which they reproduced the 

 disease in monkeys from the brains of u^hich they reisolated the 

 organism." Moreover, in 



1910, in the Philippines, by inoculating diseased material containing the 

 Treponema perteuue, Henry J. Nichols [had] produced Yaws in a monkey, 

 and from this monkey transmitted the disease to three generations of rabbits. 



In 1909 Harold Taylor Ricketts [had] discovered the cause of the Rocky 

 Mountain spotted fever, isolating the organism since known as Rickettsia 

 from man and from the ticks which he had previously proved to be carriers 

 of the disease, also from the eggs of the ticks. 



In 1911 McCoy, in California, [later] Director of the Hygienic Labora- 

 tory in Washington, discovered Bacterii/m tnlarense in ground squirrels 

 dead of an epidemic disease resembling plague, which he was then studying. 



[And in] 1913 Yamagiwa and Itchikawa, in Japan, produced cancer in 

 the ears of rabbits by repeated tar-paintings. 



Smith, in his address, " Cancer in Plants," offered the following 

 in support of his analogy between tumor strands in crown gall 

 which connect primary and secondary tumors and those malig- 

 nant animal and human tumors which " show^ a marked tendency 

 to reproduce themselves at a distance from the primary tumour 

 by means of migrating portions of their ow^n tissue," either inde- 

 pendently or by a chain of tumor cells: " MacCallum, from the 



* Fifty years of pathology, op. cit., 34; see also Smith's translation of P.isteur, 

 the history of a mind, op. cit., 341-342, Annotated list etc. 



'' Fifty years of pathology, op. cit., 34 ; also, John Drury Ratcliff, Yellow magic. 

 The stor}' of penicillin, 26, 27, N. Y., Random House. 



* Fifty years of pathology, op. cit., 34-35. 



