194 PHYSIOLOGY [Bot. Absts., Vol. VI, 



ments which are a masterpiece in manipulation and self-criticism. A few years later, De 

 Sausstjre attacked the problem. The chemistry of Lavoisier had wrought a tremendous 

 change. De Sausstjre asked a definite question and got a definite answer and established 

 quantitative relations which others had described. Aside from the discovery of certain de- 

 tails of the process of photosynthesis, our knowledge of it is practically as De Sausstjre left 

 it over 100 years ago. During this time something has been done by Dutrochet, Sachs, 

 Pfeffer, Boehm, and Draper. Most of the work of the last 30 years has been along lines 

 outlined by these workers but no new vistas have been opened nor original hypotheses formu- 

 lated. — The most important problem of photosynthesis is probably the energy relation, and 

 the old question of the action of the light in the reduction of carbon dioxid and water. Recent 

 conceptions of the nature of light and of chemical processes ought to find application to the 

 processes involved in photosynthesis, as should physical conceptions and methods of experi- 

 mentation which as yet have not been applied to the study of photosynthesis with any degree 

 of success. — For fifty years the formaldehyde theory of the development of sugars, formulated 

 by Baeyer as a mere suggestion, has received greatest recognition. The experiments have 

 followed three different lines of argument. (1) The reduction of carbon dioxid to formalde- 

 hyde by various chemical and photochemical means. (2) The detection of formaldehyde in 

 illuminated green leaves. (3) The feeding of plants with formaldehyde as the only source 

 of carbon. All these have yielded positive results. But a critical study of all the facts leads 

 to the conclusion that more experimentation is needed. — The determination of the first sugar 

 formed requires experimental proof. The fleshy joints of some cacti offer good material for 

 this type of study. Tables of certain experiments with such material, including also the 

 results of Brown and Morris with the garden nasturtium (Tropaeohcm majus) are given. — L. 

 Pace. 



METABOLISM (GENERAL) 



1317. Ciamician, G., and C. Ravenna. Sulla influenza di alcune sostanze organiche 

 sullo sviluppo della piante. Nota III. [The influence of some organic substances on the devel- 

 opment of plants.] Atti R. Accad. Lincei Rend. (CI. Sci. Fis. Mat. e Nat.) 28 l : 13-20. 1919. — 

 Having shown in a previous article that some of the fundamental compounds for the vegetable 

 alkaloids do not injure bean plants, while almost all the natural alkaloids (and particularly 

 caffein) are poisonous, he takes up the study of some derivatives of these fundamental com- 

 pounds. The bases were used as phosphates or tartrates in solution (1 to 1000) and bean plants 

 were sprinkled with these. He affirms that methyl groups, far from having a protective 

 influence on the reactive groups such as the oxyhydrate and the amino and imino groups, 

 increases the action of the fundamental substance that contains it. Other radicals also modify 

 the action of organic compounds on plants as the propyl group in conine, the acetyl group in 

 acetyl piperidine, diacetyl morphine, and acetanilide, and the radical of piperic acid in pip- 

 erine. He also found that some of the poisonous substances used on bean plants have consider- 

 able influence on the formation of starch and on its hydrolysis so that with the different re- 

 agents he obtained different results when treating the leaves with iodine, depending on 

 whether one or the other of these effects was produced. — F. M. Blodgett. 



1318. Doff, A. W., and G. W. Roark, Jr. The utilization of a-methylglucoside by Asper- 

 gillus niger. Jour. Biol. Chem. 41: 475-481. 1920. — This fungus grows very poorly on media 

 containing the glucoside as the only source of carbon, but readily on sucrose media in the pres- 

 ence of the glucoside. There was a slight difference between the activity of cultures before 

 and after spore formation. Gradual cumulative adaptation to a substitute through several 

 generations could not be demonstrated with any degree of certainty. — G. B. Rigg. 



1319. Grtjzewska, (Mrs.) Z. Contribution a l'etude de la laminarine du Laminaria 

 flexicaulis. [A contribution to the study of the laminarine of Laminaria flexicaulis.] Compt. 

 Rend. Acad. Sci. Paris 170: 521-523. 1920.— A study of the properties of this polysaccharid 

 reveals that it is very much like dextrine except that it is laevo-rotary. The author confirms 



