AGRICrLTURAL BOTANY. 431 



had begun to shrivel, and in from 1 to 5 days' exposure to diffused daylight 

 those parts of the leaves which had been directly exposed died. The I'est 

 remained green, and the plant put out new leaves. Only the epidermal cells of 

 the upper side of the exposed leaves turned brown, the cells beneath showing 

 no change. 



Similar experiments with flowers showed them to be much more sensitive to 

 the short rays than are leaves. Both flowers and leaves of hothouse plants 

 were much more sensitive to short waves than those grown in the open. Neither 

 color of the flower nor kind of plant seemed to bear any regular relation to the 

 power of resistance to the rays. Alcoholic solutions of chlorophyll showed no 

 alteration of spectrum after an exposure of from 5 to 60 minutes. 



The mycoplasm of bacteria was most sensitive to the influence of the ultra- 

 violet rays. Under exposure to direct rays for from 8 to 10 seconds all cul- 

 tures tried were killed, while none appeared to be killed by 300 seconds' ex- 

 posure to the rays which passed through mica plates. 



The effect of different luminous radiations on the movement of zoospores 

 of Chlamydomonas, P. Desroche (Compt. Rend. Acad. 8ci. [Paris], 153 {1911), 

 No. 18, pp. 829-832, dgm. 1). — After subjecting Chlamydomonas to different por- 

 tions of the solar spectrum, the author found that the radiation absorbed by the 

 chlorophyll in the alga was of 2 classes. One group excited the movement, 

 while the other checked or in some cases entirely inhibited it. 



The effect of absolute darkness on the growth of plants in laboratories, 

 J. Feiedel {Compt. Rend. Aead. Sci. [Paris], 153 {1911), No. 18, pp. 825, 

 826). — The author, by means of specially constructed boxes, claims to have been 

 able to secure absolute darkness under conditions that would permit of plant 

 growth. 



He found that it exercised a decided effect on the morphological development 

 of the plants, exaggerating all the characters that are accompaniments of etiola- 

 tion. The absence of light seemed to have no effect on the formation of an- 

 thocyanin in red cabbage, castor bean, spinach, and in cuttings of Achryanthes. 

 Absolute darkness was found to exert a definite effect on the germination of 

 lentils, the leaves being much smaller, the internodes less numerous, and the 

 stem less angular than where grown under the darkness obtained by black 

 screens. Onion bulbs grown under complete darkness were completely deprived 

 of chlorophyll, although ordinary darkness is not sufiicient to prevent these 

 plants from taking on a green coloration. 



The occurrence of hemagg'lutinin in plants, M. voN Eisler and L. von 

 Portheim {Ber. Deut. Bot. Gesell, 29 {1911), No. 7, pp. 1,19-430) .—According 

 to the authors, hemagglutinin is found present in various species of 2 genera of 

 Euphorbiacefe, 1 of Solanacefe, and 6 of Legumiuosfe. The substance is present 

 in the cotyledons or in the endosperm and very evidently acts as a reserve 

 material for the development of the seedlings. 



Is iron indispensable to the formation of conidia of Aspergillus niger? 

 M. Javillier and B. Sauton {Compt. Rend. Acad. Set. [Paris], 153 {1911), No. 

 23, pp. 1177-1180). — A. niger was grown in solutions containing iron and various 

 other substances. In the absence of iron and in the presence of a relatively 

 high amount of zinc no conidia were formed. Later it was found that the zinc 

 was the cause of this behavior. The authors claim that iron, although a very 

 important element for the growth of molds, is not fundamentally necessary for 

 the formation of conidia and their pigmentation. 



The influence of calcium on the development and ash constituents of 

 Aspergillus niger, Mile. Egbert {Compt. Rend. Acad. Sci. [Paris], 153 {1911), 

 No. 23, pp. 1175-1177). — The author describes experiments on this mold, which 

 was grown in Raulin medium to which was added various quantities of lime. 



