532 EXPERIMENT STATION EECOED. 



hydrocyanic acid, altliongh changes may take place within the leaf no reducing 

 sugar passes into the solution when the leaves are placed in water. This dif- 

 ference has been noticed in the case of a varie'y of leaves and roots as well as 

 in unripe fruits of the cherry and currant, unripe seed pods, etc. 



The differences in the blackening of leaves on exposure to water saturated 

 with chloroform or toluene seem to be proof that differential septa which break 

 down under the influence of most hormones remain intact when hydi'ocyanic 

 acid is used, although hydrolytic changes take place within the leaf under the 

 influence of the hydrocyanic acid. The authors state that, taking into account 

 the manner in which leaves change in appearance when exposed to water 

 saturated with a substance such as toluene, there can be little doubt that 

 the coloration is at least mainly an oxidation effect, and bearing in mind what 

 is known of the effect which hydrocyanic acid has in inhibiting oxidation, it 

 appears probable that differential septa remain intact because the oxidase 

 effect is eliminated in the presence of hydrocyanic acid. It is also stated that 

 oxidation processes are at a maximum in plants during the period when light 

 is inactive, and that growth takes place chiefly during this period. The trans- 

 location of nutritive materials which necessarily sets in during this period may 

 well take place because the septa are broken down and rendered i^ermeable 

 by oxidation. The differential sejita are Itelieved to be subsequently repaired 

 when assimilatory processes become ascendent. 



Light intensity and transpiration, B. E. Livingston (Boi. Gaz., 52 {1911), 

 No. 6, pp. 417-fi38, pg. 1). — The author has tested a number of forms of appa- 

 ratus to determine their value in estimating quantitatively various light inten- 

 sities to which plants in the open are subject. 



He found that the black and brown atmometers and the Hicks integrator are 

 valuable instruments for estimating the solar intensity, so far as transiiiration 

 is concerned. He thinks they should be suitable for comparing light intensities 

 in different habitats and that they are especially to be recommended on account 

 of their power of automatic integration, and also on account of the fact that 

 they give their results in terms of vaporization of a liquid, thus resembling the 

 plant in its transpiration activity. The black bulb thermometer was found one 

 of the best of the nonintegrating devices. Photographic papers are not to be 

 recommended, mainly on account of their failure to record effects of other 

 than restricted wave lengths. It is possible that photographic papers are more 

 valuable than the other instruments tested when the effects of light variation 

 on photosynthesis rather than transpiration are to be determined. 



The microscopic analysis of smoke-injured plants, P. Sorauer (Saniinh 

 Aihandl. Ahgase u. Raiichscliadcn, 1911, No. 7, pp. 58, pi. 1). — The author 

 undertook a series of investigations on the anatomical characters of plants 

 injured directly or indirectly by smoke or vapors of various sorts. Confining 

 attention to the pine he gives an account of the supposed characteristics found 

 in plants subject to smoke or fumes of sulphuric and hydrochloric acids, asphalt, 

 etc. It is stated that the amount of damage due to efiluvia of industrial estab- 

 lishments, etc., depends not alone upon the quantity of poison received, but 

 that the mode of its working, as by constant but weak or short attacks of highly 

 concentrated poisons, is also a factor in the degree of injury. 



The work is claimed to be only a preliminary attempt at differentiating 

 clearly and safely the typical smoke effects from those due to other causes. 



FIELD CROPS. 



Seedtime and harvest: Cereals, flax, cotton, and tobacco, J. R. Covert 

 ([/. S. Dept. Agr., Bur. Statis. Bui. 85, r)p. 152, figs. 27).— This is the first of a 

 series of treatises on the dates of planting and harvesting. " The series includes 



