132 ABSTRACTS 



tures in the laboratory did not die. Writer does not state whether the 

 cultures kept outdoors were exposed to sunlight as well as to cold. — 

 H. J. C. 



Effect of Elemental Sulphur and of Calcium Sulphate on Certain of the 

 Higher and Lower Forms of Plant Life. Walter Pitz. (J. Agr. 

 Res., 1916, 5, 771-780.) 



These experiments were planned because there has been some dis- 

 agreement in the past as to whether sulphur compounds increase or 

 decrease plant growth. Tests were made to observe the effect of 

 elemental sulphur and of calcium sulphate upon: (1) total number of 

 bacteria in soil (determined by plate method), (2) growth of pure 

 cultures of the organism causing red clover nodules, (3) accumulation 

 of nitrates and ammonia in soil, (4) growth of clover in soil and in agar 

 culture. The results indicate that elemental sulphur slightly stimu- 

 lates the growth of red clover, but has a harmful effect upon all the 

 other activities investigated; that calcium sulphate increases the 

 growth of the legume organism and the growth of clover, but has no 

 influence upon the general soil bacterial flora. — H. J. C. 



The Action of Schumann Rays on Living Organisms. W. T. Bovie. 



Bot. Gaz., 1916, 61, 1-29. 



The source of light was a hydrogen discharge tube, the top of which 

 was closed by a transparent fluorite plate through which the Schumann 

 rays were emitted. In general a small organism was killed more quickly 

 than a large one. The organisms used were rotifers, amoebae, infu- 

 soria, Spirogyra and fungus swarm spores. By a number of methods 

 it was shown that the action of the light is on the organism directly 

 and not indirectly by the formation of a toxic substance in the medium. 

 The extreme destructive action of these rays is the result of strong 

 absorption. Because of this absorption, the Schumann rays have a 

 marked localized action, which gives them a peculiar value for investi- 

 gations in the morphology and physiology of the cell. The change 

 produced is often one which results in an alteration of the equihbrium 

 of the water content of the protoplasm. In the Schumann region of 

 the spectrum, as in the region of longer wave length, the destructive 

 action of the Ught increases as the wave length decreases, and the light 

 of the Schumann region is much more destructive than the light of the 

 region of longer wave length. — J. T. E. 



PLANT PATHOLOGY 



A Serious Disease in Forest Nurseries Caused by Peridermium fila- 

 mentosum. James R. Weir and Ernest E. Hubert. Jour. Agr. 

 Res., 1916, 5, 781-785. 



Peridermium filamentosum Peck has been found to cause a serious 

 disease of yellow pine seedhngs at the Savenac nursery located at 

 Haugan, Mont. The fact that the same species of Peridermium at- 



