824 EXPEEIMEISTT STATION EECOED. 



effect on nitrogen fixation. In this respect the simpler compounds were more 

 pronounced than were the more complex, and it is suggested that this condi- 

 tion is not one of toxicity, but that the nitrogen of the compounds was used 

 in preference to that of the atmosphere. Urea, glycocoll, formamid, and allan- 

 toin were especially active in depressing fixation. 



Selection of nitrogen compounds by Aspergillus, "\V. Zaleski and D. 

 Pjukow (Ber. Deut. Bot. Oesell, 32 (19U), No. 1, pp. 479-483) .—As a pre- 

 liminary to a more general investigation regarding the selective power of mold 

 fungi from among nitrogen compounds, the authors have studied the relative 

 utilization by Aspergillus of nitrogenous material in case of ammonium and salts 

 amino acids supplied in a nutritive solution containing also glucose and mineral 

 salts. 



It appears that in the presence of a good carbon source ammonia is a better 

 nitrogen source for mold fungi than are amino acids individually, but it is 

 thought that a suitable admixture of the latter may prove to be still better for 

 this purpose. 



Formation of albumin in yeast, W. Zaleski and W. Iskailsky {Ber. Deut. 

 Bot. Gesell., 32 (19U), No. 7, pp. 472-479) .—The results of a preliminary study 

 of yeast supplied with nitrogen sources in different combinations are claimed 

 to support the view that yeast forms its nitrogenous material not from ammonia 

 or from amino acids separately but from a certain admixture thereof. 



Theories of fermentation, G. L. Axsbeeg {Abs. in Science, n. ser., 42 {1915), 

 No. 1080, p. 359). — According to the author, there are two types of theories of 

 fermentation, one of which deals with the mechanism by which the substance 

 fermented is converted into the end products of fermentation, while the other 

 deals with the physiological role which fermentation plays in the life of the 

 fermentation organism. 



In the present paper it is suggested that fermentation is the expression of the 

 metabolism of energy of a micro-organism. As an explanation of why a small 

 mass of organisms converts a relatively large mass of material, the author calls 

 attention to the energy requirements of the organisms, which possess a large 

 surface area in comparison with their mass, and to the fact that there are 

 excessive losses of heat due to radiation from the liquid medium in which the 

 organisms live. 



Albuminous crystalloids in potato leaves, Helena Hubert {Osterr. Bott 

 Ztschr., 64 {1914), No. 7, pp. 273-277).— The author reports that the formation 

 of albuminous crystalloids is plentiful in young leaves of potato plants grown 

 from tubers in darkness and moisture, but much less so in plants grown in 

 light and that the crystalloids diminish rapidly in etiolated plants after these 

 are exposed to light. The ci-ystalloids, which appear only in the leaves, are 

 abundant in the intumescences on the leaf surfaces, also in the interior portions 

 of the leaf, when grown under glass, but they disappear with the shrinking 

 of the intumescences. 



Anthocyanin in plants, V. Gkafe {Vmschau, 18 {1914), No. 32, pp. 643-646).— 

 This is a discussion of contributions by several authors mentioned regarding the 

 presence, composition, and significance of anthocyanins in plant cells. 



A study of chloroplasts, A. P. Ponomarew (Ber. Deut. Bot. Gesell., 32 

 {1914), No. 7, pp. 483-488). — The author gives some details of a preliminary 

 study of living chloroplasts as regards their structure, varying consistency, 

 coagulation, vacuolation, chemical behavior, and evidences noted of colloidal 

 characters. 



A contribution to the physiological theory regarding chlorophyll, D. 

 IwANowsKi {Ber. Deut. Bot. Gesell., 82 {1914), No. 7, pp. 433-447, fig. 1).— 

 Concluding a further study (E. S. R., 31, pp. 127, 128) of the relation between 



