RECENT ADVANCES IN SCIENCE 561 



high water content lead to the increase of simple sugars in 

 relation to the more complex carbohydrates, while high tem- 

 perature and low water content are associated with relative 

 increase of polysaccharides, decrease of monosaccharides, and 

 increase of pentosans. These results are highly suggestive with 

 regard to the later stages of carbon assimilation, but a very 

 great deal of work will have to be done before the materials 

 are at all adequate for a lucid understanding of the chemistry 

 of photosynthesis. 



In a long paper Stoklasa (" tlber die Radioaktivitat des 

 Kaliums und ihre Bedeutung in der chlorophylllosen und 

 chlorophyllhaltigen Zelle," Biochem. Zeitsch., 108, 109-84, 1920) 

 accounts for the greater concentration of potassium in the green 

 parts of plants by the radioactivity of compounds of that metal, 

 on account of which radioactivity these substances are con- 

 cerned in the transformations of energy in the assimilatory 

 processes. The evidence for this view will probably require 

 considerably strengthening before it obtains anything like general 

 acceptance. 



An attempt has been made by H. H. Dixon and H. H. Poole 

 (" Photosynthesis and the Electronic Theory," Sci. Proc. Roy. 

 Dublin Soc, 16, 62>-77, 1920) to determine whether there is 

 any basis for a photoelectric theory of the activity of chloro- 

 phyll. The method used by the authors consists in connecting 

 a film of chlorophyll with an electrometer in suitable fashion 

 and measuring the ionisation current developed when the film 

 was in the dark and when it was illuminated. An increase of 

 current in the latter case might be regarded as evidence of an 

 electronic theory of assimilation, electrons being driven out of 

 the chlorophyll molecule, to which action might be attributed 

 the transference of energy from sunlight to carbon dioxide in 

 the green leaf. Although such an increase of current was 

 noticed in the case of ultra violet light, no current of sufficient 

 magnitude to support the hypothesis was observable with 

 intense illumination of the visible rays. 



ZOOLOGY. By Prof. Chas. H. O'Donoghue, D.Sc, F.L.S., Manitoba 

 University, Winnipeg, Canada. 



Protozoa. — Jameson has discussed " The Chromosome Cycle of 

 Gregarines with Special Reference to Diplocystis schneideri, 

 Kunstler " {Quart. Jour. Micro. Sci., vol. Ixiv, pt. 2, Jan. 1920). 

 The nuclear stages in all the various phases of the life-history 

 have been fully investigated and discussed. The karyosome 

 of this species results from a " Micronucleus " making its way 

 inside a nucleolus, so that it is obviously composed of two 

 distinctly differentiated parts, and thus the entire Gregarine 



