222 EXPEEIMENT STATION RECORD. [Vol, 41 



turu dark. This cluinge, which is interpreted as an oxidation effect, is much 

 more rapid in the nucleus than in the cytoplasm. The facts are held to indi- 

 cate that this is also the case -with oxidation of the uninjured cell. 



Studies on the production of matter in light and shadow plants, V. B. 

 Jensen (Bot, Tidskr., 36 (1919), No. h, pp. 219-259, figs. 7).— A study of a 

 light plant iSmaj)i.s alba) and of a shadow plant {Oxalic acctoscUa) is said to 

 have sliown that carbon dioxid assimilation and daily production of dry matter 

 are very much more rapid in the former than in the latter. The equilibrium 

 point between assimilation and respiration is reached at a light intensity of 1.0 

 (Bunseu units X 100) for the former and at 0.2 for the latter. 



The luminescence of Pseudomonas luminescens, A. de CorxoN (Efndc de la 

 Luminescence du Pseudomonas luminescens. Thesis, Univ. Netichatel, 1916, pp. 

 95, figs. 18). — Results of a study of P. luminescens as here detailed are claimed 

 to show that bioluminescence is independent of respiration, but ceases with the 

 death of the cell. The phenomenon is intracellular, depending upon oxygen 

 which becomes available, though it is not known whether the oxygen is fur- 

 nished by the atmosphere or by intracellular chemical processes. Ethyl alcohol 

 at 6. 2 per cent or methyl alcohol at 10 per cent concentration, lowering surface 

 tension and semipermeability and permitting the diffusion inward of oxygon, 

 increases the duration of luminosity. Potassium cyanid augments semiperme- 

 ability but hinders respiration, resulting in the retention of oxygen by the coll. 

 Hydrogen and hydroxyl also affect permeablity and increase the duration of 

 luminescence. The shorter light waves augment the intensity of luminosity, 

 the longer having the opposite effect. 



Transpiration [in plants], R. C. Knight (Sci. Prog. [London'], 13 {1919), No. 

 52, pp. 561-566). — A review of findings and views resulting from recent study 

 by various authors named is largely epitomized in the statement that external 

 conditions, as represented by soil and atmosphere, as well as the internal cou- 

 ditious peculiar to the plant, exercise an important regulating influence on 

 transpiration. It is recognized that the problem of water movement through 

 the plant is extremely complex. 



Weather conditions and plant development, G. P. Buens {Brooklyn Bot. 

 Gard. Mem., 1 {1918), pp. 119-122). — Numerous examples are claimed to show 

 that averages extending over long periods for humidity, sunshine, wind, air 

 temperature, etc.. may conceal rather than explain the essential facts. It is 

 held that in all study of the relation of weather conditions to plant develop- 

 ment the importance of critical periods in the onvironnient must bo taken into 

 consideration. 



Contact stimulation, G. E. Stone {Brooklyn Bot. Gard. Mem., 1 {1918), pp. 

 Ji5'f-.'/79, figs. .}). — Presenting results of experimentation carried on since 1904 

 with several common plants, the author holds that contacts of plants or parts 

 thereof with one another, with wires, and with other bodies result in a reaction 

 or response which may be connected with electrical phenomena but which ap- 

 pears ttf be quite primitive and universal among plants, if not common to the 

 lower forms of life in general. Leaves appear to be particularly sensitive. 

 The nature of the reactions appears to be fundamentally similar to that of 

 touch, from which it is thought such highly differentiated reactions as those 

 of tendril and wound responses may have originated. 



Apparatus for determining' the temperature of leaves, E. B. Shreve (Car- 

 negie Inst. Washington Year Book, 11 (1918), pp. 80, 81). — A description is 

 given of an apparatus which may be used to find the surface temperature of 

 leaves without injiu-ing them, and which has been used with a large number 

 of plants of different ecological types growing under very dissimilar conditions. 



