CURRENT LITERATURE. H5 



Stiles, W., and Kidd, F. The influence of external concentration on 

 the position of the equilibrium attained in the intake of salts by plant 

 ceils. Pro. Roy. Soc. B. 90 No. B. 632, p. 448 ivith graphs. 



The authors have been conducting experiments with slices of living 

 tissues to ascertain the position of equilibrium attained in the intake of 

 individual salts, and allied phenomena. The method adopted is that of 

 placing a certain number of washed thin slices of potato or carrot in 

 different solutions the change in the electrical conductivity of which is taken 

 as a direct measure of absorption, due regard being paid to the exosmosis 

 which may take place at the same time. Kcl, NaCl or Cacl 2 solutions are 

 normally absorbed, the rate of initial absorption increasing with the con- 

 centrations of the solutions employed. Cu So t solution however causes 

 exosmosis in excess of absorption, and thus seems to destory in a way 

 the semipermeability of the cell. This phenomenon is more pronounced if 

 stronger solutions -of Cu So ( are employed. Anomalous phenomena in the 

 case of Alcl ;t are hoped to be explained in subsequent articles. The authors 

 have not investigated the mechanism of the cell concerned. 



Previous work on the subject conducted by Stiles W., and Jorgensen I., 

 and published in Ann. Bot. Vol. XXIX a'id XXXI, supports the view that the 

 method employed is a correct one. In these papers they discussed Czapek's 

 theory of plasma membrane. It may be remembered that Czapek in 1914, 

 started a theory that the mechanism concerned in the passage of salts 

 is the outermost layer of protoplasm, containing lipoid matter. With 

 reference to this theory they say that his experiments were crude and 

 unscientific and his data wrong, that the rate of exosmosis is not a function 

 of surface tension, and that there is ' not a shred of evidence ' in support of 

 some of his assumptions such as the one tbat since "solutions whose surface 

 tension with air is 0-68 are just strong enough to produce exosmosis from 

 the cell therefore the surface tension of the outermost layer of protoplasm 

 towards air must aho be 0-58". So they seriously doubt the verity of his 

 simple theory of plasmolytic membrane as the mechanism in the intake of 

 salts. 



Therefore the phenomenon of the absorption of salts seems to be more 

 complex than is usually supposed. It is not a case of mere diffusion. 



M. Balasubrahmanyam. 



Pathology 

 Hole, R. s. Plant Diseases. Indian Forester Vol. XLV (1919) 584, 

 Hole is of opinion that of recent years there has been a decided tendency 

 to exaggerate the importance of fungi and to regard them as being the 

 primary cause of most plant diseases. He feels that " if we are to make real 

 progress in controlling the diseases of our forest plants, we must develop and 

 expand the study of cecology, or as it is sometimes termed field physiology, 

 and must regard plant diseases as ooraplex problems frequently requiring for 

 their complete solution the oorabined efforts of a number of experts, such as 

 oecologists, mycologists and biological chemists." A letter written by the 

 iate Mr. Ch. Ogilvie Farquharson and reproduced from the Kew Bulletin, 

 1918, p. 353, expresses similar views. I quite agree with the opinion 

 substantiatad by good reasons, but I should be sorry if the authorities of 

 the Forest Department were to show less interest in the work done by their 

 mycologists. 



E. B. 



U80-P-19 



