iqiq] current literature 515 



characters. He was successful in finding practically all the new combinations 

 that were theoretically possible. 



The Mendelian explanation runs as follows: The character of the hybrid 

 zygote itself is maternal, as is to be expected from the cytological behavior 

 during conjugation. The reduction division takes place during the first 2 

 nuclear divisions of the germinating zygote, but 3 of the resulting nuclei degen- 

 erate, so that the cells of the mature filament all have a common ancestor in 

 the fourth nucleus; hence segregation appears in the first hybrid generation, 

 but of course all of the cells of a given filament are alike. Such facts would 

 furnish excellent support for our theoretical mechanism of inheritance, but 

 the author could not be positive as to whether he was deahng with an Fi or 

 an F2 generation. It is to be hoped that he will discover how to cultivate this 

 material in the laboratory, and carry the work further under rigid experimental 

 control. — Merle C. Coulter. 



Enzyme action. — Van Laer* reports some observations on the nature of 

 zymogens, which are claimed to confirm the results of Ford and Guthrie, 

 who had shown that the increase of the amyloclastic activity of papaine with 

 barley meal is not manifested when the infusion is kept in direct contact with 

 the proteo-clastic ferments. The yeast infusions were obtained from yeast pre- 

 pared according to the Lebedeflf method. The addition of papaine to yeast 

 juice destroyed the catalase and zymase. In the state of zymogens, there 

 was shown greater stability and resistance to the factors of inactivation. The 

 hefanal extract of yeast in the presence of antiseptics showed a measurable 

 degree of inverting activity. This inverting agent was amylase. The diastase 

 and papaine had no influence upon the hefanel infusion even after a 24 hours' 

 digestion. Observation is made upon the intensity of autofermentation. 

 After the latter there remains some amylase which is sensitive to papaine. 

 This sensitiveness is expressed in the data as the decrease of the percentage 

 of sugar inverted from 25 .6 to 19 when papaine was added. Certain cellulary 

 materials, as soluble or incoagulable protoplasmic products, decreased the 

 activity of sucrase according to the concentration. In the presence of small 

 quantities of these substances the rapidity of hydrolysis of saccharose is hardly 

 modified. Extracts of yeast inactivated by acetone give a notable increase 

 of inverting power when added to solution of papaine or active anylase, the 

 yeast cells in this respect behaving like cellulary bodies. This increase is due 

 on the one hand to the increase of sucrase, and on the other to the decrease of 

 cellulary substance in the digestion products. — A. M. Gurjar. 



Buried weed seeds. — Miss BRENCHLEy,^ on the basis of considerable 

 investigation, makes the following statement concerning the longevity of weed 

 seeds in agricultural soils: "The changes in the proportion of arable and 



n' AX Laer, Henri, Zeits. fiir Garungsphysiologie 6:169-175. 1918. 



7 Brenchley, Winifred E., Buried weed seeds. Jour. Agric. Sci. 9:1-31. 1918. 



