600 Third European Journey 



August 2: As indicating the long continued virulence of certain strains 

 of Bacterium tumefaciens, witness the Hop strain through col. 1 (1915) 

 i. e. on agar since 1915. It was isolated from a hop tumor in 1906 or 1907. 

 We obtained our first infections with it in 1907, on hop et cetera. Now, 

 of the 190 young Ricinus plants which I inoculated July 24th (1924), 

 every one but 3 have given fine tumors tn nearly or quite every needle 

 prick! One of these three shows no pricks and may have been overlooked 

 and of the other 2, one shows a tiny tumor. I consider this very remark- 

 able because it is 18 years since first isolations and 9 years since the sun- 

 flower col. 1 re-isolation was first cultivated on a^ar and in all this time 

 it has not been reinforced by passage through plants ! Of the 2 exceptions 

 (which I will do over) one shows nothing and the other very slight tumors. 



August 9: Reinoculated the 3 Ricinus plants (see Aug. 2) with 4 day 

 whey agar, also as checks two younger Ricinus plants — all from one tube. 



August 12: Examined inoculated Ricinus plants and made 12 photos 

 (each 2/3 natural size) . I see no evidence of tumors with roots or leaves, 

 although they cover a large part of the top of the stems and rim out on 

 many leaves (petioles and blades). 



Two days later he happened to show his Ricinus inoculations 

 to Secretary of Agriculture Henry C. Wallace. On the previous 

 April 23 the Secretary had seen some crown galls, at a time when 

 Smith was working at potentiometer hydrogen-ion determinations 

 of crown gall of sugar beet, sunflower, ricinus, tropaeolum, and 

 other plants. His main reason for seeing the Secretary was to 

 protest against a proposed removal of some of the Department's 

 facilities to government-owned land on the Potomac twenty miles 

 distant. He had recently been elected president of the American 

 Association for Cancer Research, and his enthusiasm to continue 

 his work without any change in working conditions was evident. 

 In 1922 the Secretary had been given an account of Smith's 

 research achievements, and his already quoted response showed 

 that he recognized the value to the Department of such a world 

 known scientist in its employ. 



During their conference of August 14, Secretary Wallace sug- 

 gested to the veteran scientist a journey to Europe. They " got to 

 talking about agricultural research in the United States and in 

 Europe, and he said, " How long is it since you were over there .-^ 

 Smith answered, ^- " ' Eleven years.' ' Don't you think it would 

 be a good idea to go over there and see what they are doing? 

 the Secretary asked. The response was, " ' I should like to, would 



" Diary, Aug. 14, 1924. 



