196 TUMOURS OF EUCALYPTS AND ANGOPHORAS, 



be hard, and do not in any way appear to weaken the trees. In 

 many cases, the diseased trees have completely outgrown the 

 disease, and in these instances there has been but little increase 

 in size of [the] original, knots. From our observations, the dis- 

 ease does not seem to seriously injure the growth of the tree. 

 Numerous attempts to isolate a pathogenic organism have re- 

 sulted in failure, although we still believe the galls may be 

 caused by such an organism." 



Quite recently three papers by Dr. Erwin F. Smith, of the 

 U.S. Department of Agriculture, have come to hand, which have 

 a very important bearing on the problem of the shoot-bearing 

 tumours of Eucalypts.* 'J'hese also are to be found only in 

 a few libraries. '1 hey are important because they relate to the 

 first records of natural, axillary, shoot-bearing tumours caused by 

 soil-organisms; and axillary and other special tumours produced 

 by artificial inoculations. We give the following extracts from 

 these : — 



Dr. Erwin Smith says in his paper published in August, 1916: 

 " Last winter, I discovered that when growing plants are inocu- 

 lated in the vicinity of dormant buds, a new type of tumor is 

 produced. This tumor bears, on its surface, diminutive abortive 

 shoots (vegetative or floral) and in its interior, along with the 

 cancer-cells, numerous fragments of embiyonic tissues, variously 

 fused and oriented, often upside down and curiously jumbled 

 These tumors have never been seen by the writer in nature, or 

 at least if seen, not recognised as crown-gall tumors, but un- 

 doubtedly we shall now find them." [Then follows reference to 

 a footnote "As this goes to press, I have had confirmation of 

 this belief, having received from a florist in Massachusetts, a 

 crown-gall of the rose showing abortive shoots growing out of 

 stem-tumor."] Dr. Smith continues— " These tumors have all 



* ''Further Evidence as to the Relation between Crown-Gall and 

 Cancer,'* Proc, Nat. Acad. Sci. U. S. A., ii., p. 444 (August, 1916). 

 "Mecanism of Overgrowth in Plants," Proc. Amer. Phil. Soc. Philadelphia, 

 Ivi., No. 6, p. 439 (August, 1917). "Embryomas in Plants (produced by 

 Bacterial Inoculations)," Bulletin Johns Hopkins Hospital, xxviii., No. 

 319, p.279 (September, 1917). 



