388 EXPERIMENT STATION RECORD. 



to the ordinary eiizyiiies of vegetative organisms. Diastase, being ensy 

 of extraction, was the one selected, and for the experiments it was 

 prepared from ordinary malt. The mode of experiment was to pre- 

 pare some extract of malt by infusing the ground grains with water 

 or salt solution aud expose half the (piantity to strong light, either 

 solar or electric, for varying times; then measured ([uantities of the 

 exposed aud unexposed halves were allowed to act upon ii thin starch 

 preparation at about the ordinary laboratory temperature. When 

 digestion was well advanced, both tubes having been boiled with 

 excess ot Fehlmg's solution, the resulting precipitate was collected, 

 washed, ignited, aud weighed as copper oxid. 



The results of the experiments were as follows: (1) Light, whether 

 solar or electric, exercises a destructive effect upon diastase; (2) the 

 deleterious influence is confined to the rays of the violet end of the 

 spectrum, the others being slightly favorable rather than destructive; 

 and (3) the coloring matter of the barley husk acts as ;\ screen, 

 preserving the diastase from the destructive effect of light. 



The destructive influence continues after the exposure to light is 

 discontinued, the exposed solution getting weaker and weaker until it 

 has 110 (^hastatic action. The part of the solution kept in darkness 

 maintained its diastatic power unimpaired for more than a month, by 

 which time the exposed part possessed no power to act upon the starch. 



Insectivorous plants, P. Geddes (Chapters lit Modern Botany, 

 18'Ji, PI) 1-59, Jif/s. 4; abs. in *SV-i. Go,s., n. ser., 1 {1894), No. 7, pp. 

 159). — Illustrated descriiDtions are given of the knowm insectivorous 

 plants, with summaries of the latest experiments upon their physio- 

 logical action. The author still insists on the importance of insect 

 catching as a source of nitrogen to the plant, in spite of the contention 

 of recent authors that the secretive glands of pitcher plants are not 

 special and essential adaptations toward insect capture and digestion, 

 but mere water stoinata which play the part of regulators of transpira- 

 tion,— l. O. HOWARD. 



Revision of the genus Lathyrus in North and Central America, T. G. White, 



(Torrey Bui., 21 {1894), No. 10, pp. 444-458). — A prehiniuary revision of the genus 

 and description of new species. 



The Smilaceee of North and Central America, T. Moron(; (Torrey Bid., 21 (1894), 

 No. lO, pp. 419-44o). — A r(?vi,sion of the genus aud description of new species. 



Popular American plant names, F. I). Behgen {Bot. Gaz., 19 (1894), No. 11, pp. 

 429-444). 



On the mechanism of plant respiration, L. Maquenne (Compt. Iioid., 119 {1894), 

 No. 17, pp 097-699). 



Nature and distribution of attraction spheres and centrosomes in vegetable 

 cells, .J. H SuiiAFiXER (Bol. Ga:., 19 (1894), No. 11, pp. 445-459, pi. 1). 



The periodic reduction of the number of chromosomes in the life history of 

 living organisms, E .SiRASurRiiER {Ann. Bot., 8 {1894), No. 31, pp. 281-316). 



Geotropic sensitiveness of the root tip, W. Pfefeer {Ann. Bot., 8 {1894), No. 

 Si, pp. Sr7-3.'0). — A preliminary paper in which it is shown that only the tip of the 

 root 18 geotropically sensitive, and it induces the curvature of the root. 



