1918] CURRENT LITERATURE II5 
optimum temperature for the former is put at about 20° C., for the latter 30°. 
The fact that no injury appears in the infected cells, but only in the cells sur- 
rounding them, is thought by Marns to be due to starvation brought about by 
withdrawal of foods to the infected region. It is possible, however, that the 
diffuse outward from the infected cells. The growth of the rusts and the 
development of spore pustules were increased when some carbohydrate was 
ed to the nutrient solution, and the conclusion is drawn that “the obligate 
parasitism of the rusts is probably explained by their requirement of some 
transitory or nascent organic products related to the carbohydrates which they 
obtain in the living plant.’’ This conclusion is hardly in accord with the 
statement made by RussELL" that wheat plants whose photosynthetic activity 
has been seriously decreased by lack of potash, and whose carbohydrate content 
is therefore low, are especially susceptible to attacks of rust. Further work 
seems necessary to clear up the situation. 
Brooks and Coo.ey® find that in inoculations on apples all of the fungi 
tested grew at o° C. except Fusarium radicicola and Glomerella cingulata, the 
former making no growth at 15° and the latter none at 10°. Sphaeropsis 
malorum had produced no evident rot at 15° by the end of a week, the species 
of Penicillium and Neofabraea at 10° by the end of two weeks, while Sclerotinia 
cinerea produced measurable rots at 5° in one week and at o° in two weeks. 
Neofabraea malicorticis had an optimum at 20°, Fusarium radicicola at 30°, 
and all the other fungi at 25°. When grown on corn meal agar in Petri dishes, 
all the fungi showed the same optimum and maximum as in the fruit inocula- 
tion experiments. With most of the fungi the initial incubational stages of 
growth on the fruit were more inhibited by low temperatures than the later 
ones. The results of the investigation show the importance of immediate as 
compared with delayed StORAge; the value of temperatures of 5 or 10° in short 
periods of storage, and of o° in longer ones; and further that the minimum 
PD varies with the prevalent fungus and with the variety and maturity 
of the fru 
In an as of the growth of fungi on nutrient solutions by 
Hawkins’ it was found that Aspergillus niger, Penicillium glaucum, and 
Botrytis cinerea grew readily in solutions of potassium and calcium nitrate, 
sucrose, and glucose in which the diffusion tensions were much higher than the 
total diffusion tensions of the dissolved substances in the juices of their host 
plants.—D. H. Roser 
"RussEtt, E. J., Soil conditions and plant growth. 2d ed. London. 1915 
(pp. 41, 
® Brooks, CHaRLEs, and Coo.ey, J. wa olay temperature relations of apple-rot 
fungi. Jour. Agric. Research 8:139-163. 
3 Hawkins, Lon A., Growth of die a in concentrated solutions. Jour. 
Agric. Research ye agente. 1916. 
