CURRENT LITERATURE 
NOTES FOR STUDENTS 
Crown gall.—Recent developments in the study of crown gall and its rela- 
tion to animal cancer have been presented by Smira in several papers. The 
first? of these, in point of completion although not in time of publication, is a 
succinct account of remarkable growth phenomena resulting from the action 
of Bacterium tumefaciens when inoculated into special tissues of plants. Four 
cases are Sistngnshet 
1. Whent dal cambium is inoculated, this tissue loses its tendency 
to form mature structures having definite orientation. Instead, the cells 
continue to divide rapidly, forming large masses of mostly embryonic par- 
enchyma within which scattered and irregularly arranged xylem and phloem 
elements are differentiated. The process recalls that described by Lamar- 
LIERE? in the galls of Gymnosporangium and aptly designated by him as 
“parenchymatization.” 
2. When the cortical parenchyma is infected, a somewhat similar develop- 
ment takes place. The cell divisions succeed each other so rapidly that the 
cells in the proliferating tissue remain small in comparison with the normal 
parenchyma, and appear to remain continually in an embryonic state. In 
time, however, there is a tendency to develop vascular elements, and these are 
then arranged in a more or less well defined stele. The vascular system of such . 
tumors has no connection with that of the stem, consequently the galls 
die from imperfect nutrition and lack of water. The galls of these two t 
exhibit no external differentiation. They include all the forms of crown gall 
described in former papers. 
3. A more remarkable condition is brought about when the crown gall 
organism is inoculated into the leaf axils of young growing plants (species of 
Pelargonium, Nicotiana, Lycopersicum, Citrus, and Ricinus). The tumors 
ae | 1 P nape vei Asem +, 
t SMirH, Erwin F., Crown gall 
a changed stimulus. Jolie: Agric. Research 6: ae pls. 18-23. 1916; see also 
Le cancer est-il une maladie du regne végétal? Premier Congress Internat. Path. 
Comp. Vol. II. 1912; Cancer in plants. Proc. 17th Internat. Souiies of Medicine. 
Vol. III. Pathology. London. 1913; Further evidence as to the relation between 
crown gall and cancer. . Nat. i i tha 
crown gall of plants is cancer. Science 43:871-889. 1916; Chemically induced crown 
galls. Proc. Nat. Acad. Sci. 3:312-314. 1917. 
? Rey. Bor. Gaz, 427153. 1906. 
3 Rev. Bor. Gaz. 52:75. I91I; 55:257- I913- 
3 
