ZOOLOGY AND BOTANY, MICKOSCOPY, ETC 617 



of locust disease. A difficulty which obtruded itself in his earlier work 

 arose from the impossibility of keeping exalted cultures up to standard 

 virulence. During the locust destruction campaign in Tunis in the 

 present year, d'Herelle has devised a new technique which has given 

 exceedingly satisfactory results. Starting from a culture of the bacillus, 

 passages are effected until the bacillus arrives at such a state of virulence 

 that the death of the experimental locusts follows an injection, in less 

 than eight hours. Immediately after the death of the insects, the bodies 

 are dried carefully in a sulphuric acid dessicator at the laboratory tem- 

 perature, and after pulverization, placed in small glass tubes, which are 

 subsequently sealed off in the Bunsen flame. In these conditions the 

 virus conserves itself without alteration for at least two years. When 

 required for use, a tube is opened, emulsified with sterile distilled water, 

 and cultures therefrom made on agar at room temperature. Sub-cultures 

 are then made in broth consisting of 5 grm. pepton, 5 grm. meat 

 extract, and 5 grm. of sodium chloride per litre. During the course of 

 the campaign the fresh bodies of infected locusts are collected, and then 

 dried and pulverized as above described, the powder obtained being 

 used for starting the infestation in the following season. 



Disease of the Tomato.* — Y. Peglion describes a disease of the 

 tomato which is characterized by withering of the leaves and stalks. 

 The disease is practically limited to the vascular regions, which become 

 brown and soft. Cultivations made on o-elatin and affar showed a short 

 non-motile bacillus in roundish colonies, at first white, afterwards be- 

 coming yellow. The disease was reproduced by inoculating healthy 

 plants with pure cultures. The bacillus would appear to belong to the 

 group of vascular bacteria described by Erwin P. Smith. The disease 

 seems to be the same as that prevalent in America, but differs therefrom 

 in that it is more localized and circumscribed. 



* Atti R. Accad. Lincei, xxiv. (1915) pp. 157-60. 



Dec. loth, 1915 2 u 



