No. 1, October, 1920] PATHOLOGY 37 



whitish down of conidiophores, principally on the leaves, abnormalities in growth of the vege- 

 tative parts, and abortive development of the ear, resulting in partial or complete sterility. 

 These effects of the disease are described and illustrated." — The disease is caused by Sclero- 

 spora philippincnsis n. sp. which is fully described and illustrated. 8. maydis of Reinking 

 is a synonym. Oospores have not been observed. The fungus is compared critically with 

 other oriental Sclerosporae. — Conidia are produced abundantly at night; they germinate 

 promptly by production of a tube and at temperatures between 6.5° and 25°. Desiccated 

 conidia lose their vitality. — An undescribed species of Sclcrospora, producing only oospores, 

 has been found on Saccharum spontaneum, a common wild grass. — D. Reddick. 



2G1. Winslow, C.-E. A., and I. S. Falk. A contribution to the mechanism of disinfection. 

 [Abstract.] Absts. Bact. 4: 2. 1920. — "The view of Chick and other earlier workers that the 

 rate of dying of bacteria follows the orderly course of a monomolecular reaction has recently 

 been challenged by Brooks, who shows that in the case of hemolysis of blood cells and infer- 

 entially in the case of bacterial death, the logarithmic values corresponding to the number 

 of surviving cells do not lie on a straight line. He concludes that the shape of the curve is 

 dependent essentially upon two independent variables; (1) the velocity at which the physico- 

 chemical changes are going on in the protoplasm of the cells; and (2) the variations in resist- 

 ance of the individual cells to the toxic substances present. — From somewhat exhaustive stud- 

 ies of the rate of mortality of colon bacilli in water and salt solutions we are able to confirm 

 Brooks' conclusion as to the shape of the curve, since we find the rate of reduction is suf- 

 ficiently slow to permit of careful observation we do obtain an inflected curve rather than a 

 straight line. — We believe, however, that these results can be explained more simply without 

 Brooks' postulate of a specific factor, by the following assumptions: — That the death of a 

 cell is due to a reaction A — >M and a reaction M — >B. Each of these reactions is of a mono- 

 molecular order (and there are probably many more than two; but two will serve for our argu- 

 ment). The velocity of the second reaction at any time is dependent upon the concentration 

 of M, and hence, is dependent upon the velocity of the first reaction. Disinfectants and toxic 

 substances accelerate one or the other of these reactions, and hence lead more rapidly to death. 

 Differences in the ages of the individual cells, we may consider, are accompanied by differ- 

 ences in the concentration of one or the other substance, — and these differences determine 

 the velocity of the toxic reaction. Since the velocity of a reaction is always dependent upon 

 the concentration of reacting substances, such variations from monomolecular reaction 

 curves as have been observed in studies of disinfection, hemolysis, and other processes are 

 easily explained quantitatively by the assumption of two, dependent, monomolecular reac- 

 tions; of different rate; and exactly such curves are figured by Mellor in his 'Chemical 

 Dynamics and Statics.'" — [Authors' abst. of paper read before Soc. Amer. Bact.] 



262. Wober, A. Versuche zur Bekampfung des roten Brenners der Reben im Jahre 1918. 

 [Investigations in the control of red leaf burn of grape in 1918.] Allgem. Weinzeitg. 36: 9-10. 

 1918. — Reports use of a number of proprietary compounds for control of leaf burn, caused by 

 Pseudopeziza tracheiphila, in Austria Winter treatment with 40 per cent ferrous sulfate gives 

 better results than the use of 10 per cent sulfuric acid, but winter treatment must be supple- 

 mented with summer spraying. — Of the various standard and proprietary mixtures tested 

 Bordeaux mixture and "Bosna" were best. [Through abst. by Matouschek in: Zeitschr. 

 Pflanzenkr. 29: 263. 1919 (1920).]— D. Reddick. 



263. Wolff, W. H. Influence of the prevention of leaf blight on the growth of nursery 

 cherries and pears. Amer. Nurseryman 31 6 : 110. 1920. 



