240 PHYSIOLOGY [Bot. Absts., Vol. IV, 



amount of glucose absorbed from the solutions was greatest under conditions of greatest illu- 

 mination. The same weight of roots absorbed more sugar in weak illumination than in 

 strong illumination, but for the whole plant the same weight absorbed practically the same 

 amount of glucose in the various light intensities. — The pea is thus incapable of augmenting 

 the absorbing power of the roots in a manner that would enable it to take up a greater 

 quantity of organic carbon from the soil. No compensation or parallelism exists between the 

 use of CO2 by the leaves and absorption of organic compounds by the roots. — F. B. Wann. 



1597. Hamilton, A. G. The effect of sunlight on plants. Australian Nat. 4:89-90. 

 1919.— See Bot. Absts. 4, Entry 224. 



1598. Lagerberg, Ivar. Vergleichende Untersuchungen liber die WiderstandsfShigkeit 

 der Sporen und der vegetativen Formen einiger sporenbildender Bakterien gegenuber ultra- 

 violett Licht. IV. Mitteilung fiber die Wirkung der ultravioletten Strahlen. [Comparative 

 studies of the resistance of spores and vegetative forms of spore-forming bacteria to ultra-violet 

 light. IV. On the action of ultra-violet rays.] Zeitschr. Immunitatsforsch 28: 186-197. 1919. 

 — Using Bacillus subtilis, B. mesentericus , B. megatherium, and two strains of B. anthracis, 

 the effects of ultra-violet light were tested in the usual way. Death occurred sooner when 

 spores and vegetative cells were dry, with little difference between them. Moist spores of 

 B. anthracis resisted the rays 8 to 10 times as long as dry spores, but the other bacteria did not 

 show this effect. The vegetative cultures were 6 hours from spores at 36°C. and were tested 

 for the presence of spores by treatment with 3 per cent formaldehyde for 3 minutes or 1 per 

 cent for 10 minutes as the spores of all these species resists this treatment while the vegetative 

 forms do not. — C. W. Dodge. 



1599. Mast S. O. Reversion in orientation to light in the colonial forms, Volvox globator 

 and Pandorina morum. Jour. Exp. Zool. 27:367-390. 1919.— (1) Volvox and Pandorina are 

 usually positive in weak, and negative in strong light if they are dark-adapted ; but if they are 

 light-adapted the opposite sometimes holds. (2) If dark-adapted colonies are exposed in 

 constant illumination, they are neutral at first, then they become positive, later negative, 

 and finally positive again. The higher the illumination the shorter the time required to pass 

 through these stages, but in the higher illuminations it requires much more energy to induce 

 the changes in orientation, than it does in the lower illuminations. (3) Reversion is, to a 

 certain extent, dependent upon the amount of energy received, but under certain conditions 

 it appears to be dependent primarily upon the time-rate of change in illumination. (4) 

 Reversion is not controlled by photosynthesis. Red and yellow lights in which photosynthe- 

 sis is relatively strong have little effect on reversion, while green and blue in which photosyn- 

 thesis is relatively weak are nearly as effective as white light. (5) The rays which have the 

 greatest stimulating efficiency (green and blue) are the most potent in producing reversion. 

 (6) The sense of orientation is dependent upon the physiological state of the colonies as well 

 as upon the constitution of the culture medium. It is also dependent upon the age of the 

 colonies. Young colonies are more likely to be negative than old ones. (7) Reversion is 

 probably associated with changes in permeability. — S. O. Mast. 



1600. Mast, S. O. Effect of chemicals on reversion in orientation to light in the colonial 

 form, Spondylomorum quaternarium. Jour. Exp. Zool. 26:503-520. 1918.— (1) Acids and 

 some narcotics, especially chloroform, when added to the culture solution, cause negative 

 specimens of Spondylomorum to become strongly positive. They have no effect on positive 

 specimens except perhaps to make them more strongly positive. Only a few of the numerous 

 other substances tested have any effect, and these produce only a very slight tendency toward 

 positive orientation. (2) Increase in the concentration of the culture solution, produced by 

 adding culture solution part of which has evaporated, or to which sodium hydrate has been 

 added, causes positive colonies to become .strongly negative. Decrease in concentration, 

 produced by adding a less concentrated culture solution, causes negative colonies to become 

 strongly positive. A decrease, produced by adding pure water, has only a very slight effect, 



