ABSTRACTS 577 



the corpuscles are removed from the defibrinated hog-cholera-immune 

 blood, the heat causes coagulation and destroys the commercial value 

 of the serum. Complete removal of the corpuscles by centrifugaliza- 

 tion alone has proved impractical ; but if they are first agglutinated by 

 the addition of extract of the common white navy bean, complete sepa- 

 ration from the serum is quite easy. The serum thus prepared has 

 no harmful properties due to the bean extract; and can be heated for 

 thirty minutes at 60° without undergoing any change. — H. J. C. 



PLANT PATHOLOGY 



Crown gall Studies; Showing Changes in Plant Structure Due to a Changed 

 Stimulus. (Preliminary paper.) Erwin F. Smith. (J. Agr. Res., 

 1916, 6, 179-182, with six plates.) 

 This is a continuation of work on crown gall in which its similarity to 



human cancer is pointed out. This paper describes some new points 



in the pathology of the disease. — H. J, C. 



Transmission and Control of Bacterial Wilt of Cucurbits. F. V. Rand 

 and Ella M. A. Enlows. (J. Agr. Res., 1916, 6, 417-434.) 

 It was shown several years ago by Erwin Smith that this disease 

 (due to B. tracheiphilus) was transmitted by the striped cucumber 

 beetle {Diabrotica vitiata Fab.). The present work confirms this con- 

 clusion, and shows that the principal summer carriers of the disease 

 are all species of Diabrotica. There is no evidence of spread through 

 the soil (unless the roots are injured) or by means of infected seed. The 

 disease can be controlled by early treatment with Bordeaux and ar- 

 senate of lead. Experiments are now being carried on to learn how to 

 control the beetles that spread the disease. — H. J. C. 



Further Evidence that Crown Gall of Plants is Cancer. E. F. Smith. 



(Science, 1916, 43, 871-889.) 



After a brief survey of the main sub-divisions of the forms of cancer 

 and their outstanding characteristics, the author presents a powerful 

 argument for the "parasitic origin and essential unity of the various 

 forms of cancer occurring in men and animals." The evidence is essen- 

 tially presumptive, being drawn from the striking resemblance between 

 Crown Gall of plants, wliich the author has proved to be caused by the 

 Bacterium tumefaciens, and human cancer. The domination of the 

 morphologists in cancer research is deplored and the attention of the 

 experimental biologist and the bacteriologist is invited. So firm is the 

 author's conviction of the parasitic nature of this malady that he ex- 

 claims: "I am now persuaded that the solution of the whole cancer 

 problem lies in a study of these plant tumors." The discovery reported 

 that the Crown Gall organism will produce teratoid tumors with regu- 

 larity in various plants, not only in dormant buds but in the leaves, is 

 a most astonishing and important contribution. — C. M. H. 



