606 Third European Journey 



distance." In his address he had mentioned the question of the 

 location of the bacteria, intracellular or within the cells, as a point 

 still under discussion: " Les bacteries du Crown-gall sont-elles 

 dans les espaces intercellulaires ou bien dans les cellules? Cette 

 question est jusqu'a present un sujet de discussion. En quelque 

 lieu que soient loges ces micro-organismes, leur action est, je 

 pense, toujours de nature physico-chimique et non mecanique." '^^ 

 Before Dr. Smith had left the United States, Dr. Riker had 

 again reported observing the bacteria in the intercellular spaces. 

 The bacteria, seen between cells in living uncontaminated sections 

 placed in agar, had been observed to grow, had been isolated, and 

 identified.*^* Nothing from Dr. Smith's diary intimates that he 

 knew this. But, after he had gone to southern France and Italy 

 and returned to Paris, he read " Pinoy's note on Plant Cancer or 

 Crown Gall " ^^ and wrote the following in his journal February 

 6, 1925: 



Pinoy and Magrou were unable to find bacteria in crowngalls on Pelar- 

 gonium by Riker's method. Pinoy found in large peripheral tannin cells 

 short rods often paired which he takes to be the bacteria. He did not find 

 them either in or between the small cells of the tumor (Magrou's statement 

 to me and my own observation of Pinoy's slide) . His sections were fixed 

 in [ - } with iron sulphate, washed free, and stained in indigo blue 

 and counter-stained with fuchsin. The bacteria are red and the tannin 

 granules black. There were fewer of these in the cells containing the bac- 

 teria. He emits the hypothesis that in crowngall, as in the nitrogen 

 tubercles of Leguminosae, the bacteria are not in the cells that form the 

 tumor. This I doubt. They are not, it is true, in the fine hyperplasia of 

 the Legume nodules, but the swollen cells in which they occur are so nu- 

 merous that they make up the bulk of the tumor. He thinks Riker mistook 

 for crowngall bacteria B. fluorescens, very frequent on tomato and tobacco 

 and always intercellular. This I also doubt. Riker is I think too good a 

 worker for that. 



On October 14, Dr. and Mrs. Smith left Paris and, after 

 stopping a few days at Avignon and Nimes, journeyed on to 

 Montpellier where Dr. Ravaz escorted them about the agricultural 

 college and botanist Boyer took them through the Arboretum. 



*' Le Crown-gall, op. ch., reprint, 7. 



** Some rel. of the crowngall org. to its host tissue, Jour. Agr. Res. 25(3): 119- 

 132, at p. 130, July 21, 1923; also Bot. Rev., op. ch., 12: 70. 



*^ P. E. Pinoy, A propos du cancer des plantes ou crown gall, C. R. Acad, des Sci. 

 180: 311-313, Jan. 26, 1925. 



