430 First European Journey 



the etiological significance of the plasmodium has not been made out, since 

 all sorts of non-parasitic soil organisms are likely to occur in galls when 

 they are of some size. Toumey inoculated only ten plants altogether and 

 obtained successful infections on three only of the ten.''^ The inoculations 

 were made in a country where the disease prevailed extensively and with 

 spore material taken from the cut surface of the gall. The Dendrophagus 

 spores, therefore, would be liable to contamination with anything occurring 

 on the cut surface, especially the virulent schizomycete which can be demon- 

 strated to be present in such galls and with which in pure sub-culture the 

 disease can be reproduced, if the plants are in a young and actively growing 

 condition, 100 times out of 100. 



Drs. Smith and Townsend in their preliminary announcement 

 of "A Plant-Tumor of Bacterial Origin" (1907) proposed for 

 " the organism causing these tumors the name Bacterium tume- 

 faciens," new species, " a schizomycete causing rapid multiplica- 

 tion of the young tissues of Chrysanthemum fnitescens. Primus 

 per ska, etc." At that time their experiments on crown gall of the 

 peach were not completed; but they mentioned Toumey' s work 

 as not clearly establishing that it was due to a myxomycete. They 

 admitted that " the cause, in spite of much study by many persons, 

 [was] still in dispute," and acknowledged that the disease had 

 been proved to be communicable by the experiments of Thaxter, 

 Halsted, Selby, Toumey, W. E. Smith, von Schrenk, Hedgcock, 

 and others. When minced galls were buried in the earth near 

 the roots of sound trees, crown galls developed. 



Sometime between February, 1904, and March, 1906, Smith had 

 examined fresh, unstained, thin sections of undecayed galls, pre- 

 pared by Townsend. He had detected bacteria in the interior of 

 the gall material but was never thereafter prepared to say that 

 these were actually the bacterium later isolated. Seeing bacteria 

 in small clumps so positively, he (or Dr. Townsend) directed 

 Miss Haskins " to make agar-poured plates from the interior of 

 suitable galls; and with the bacteria so obtained, inoculations on 

 healthy daisy plants." *® 



The work proceeded for " many months without positive 

 results." ^'' 



^^ An inquiry into the cause and nature of crown-gall, op. cit., 63. 



** E. F. Smith, N. A. Brown, and C. O. Townsend, Crown-gall of plants: its 

 cause and remedy, U. S. Dep't of Agric, Bur. of PI. Ind. Bull. 213: 22 (issued 

 Feb. 28, 1911). Miss Haskins's work summarized, pp. 20-25. 



^'' Idem, 22. 



