, 909 ] CURRENT LITERATURE 343 



Oedogonium has grown for a considerable time in distilled water in the light, 

 a transfer to darkness or to a dilute nutrient solution causes a development of 

 zoospores. Resting cells of Haematococcus, kept in darkness for some time, pro- 

 duce swarmspores upon being illuminated or supplied with cane or grape sugar. 



Frfxxd finds the chemical nature of the medium rather than its physical or 

 osmotic character the important consideration in the asexual reproduction. In 

 contrast to this, Livingston found the osmotic character of the media the main 

 consideration in determing the form of Stigeoclonium.— Wm. Crocker. 



Phototropic response— Blaauw, 18 working with the seedling of Arena 

 saliva, concludes that the intensity of the light, multiplied by the least time of 

 exposure necessary to give a phototropic response, is approximately a constant. 

 The intensities used varied from 0.000439 to 26,520 Hefner candles, and the tim 

 of exposure from 13 hr. to o . 001 sec. The product of the exposure in seconds by 

 the intensity in Hefner candles averages about 21 and varies from 16.9 to 26.5. 

 This, of course, hardly looks like a constant; but the variation is attributed to the 

 individual differences of the seedlings. The intensity of the light was measured 

 with a Weber photometer, and the observation of the response was made two 

 hours after the end of the exposure. The author says, "The essential condition 

 for the production of a phototropic curvature is the supply of a definite quantity of 

 radiant energy; whether this quantity be supplied in a very short time or extremely 

 slowly, is a matter of indifference."— Wm. Crocker. 



Spraying potatoes.-A recent bulletin" summarizes the results of the seventh 



year expen 



ased 



re 



the yield 39 bushels per acre and three sprayings increased it 29 . 5 bushels, a tnougn 

 •wh early and late blight were wholly absent and there were but few flea beetle* 

 In fourteen "farmers' business experiments" including 

 No due to spraying was 18.5 bushels per acre; the average total expense o 

 spraying, $ 4 . 30 per acre; and the average net profit, $8.53 P"" acre - . ln ™ e °„ 

 tl * experiments spraying was unprofitable. Eleven "volunteer expenmenters 

 sported gains averaging 66 . 3 bushels per acre.— F. L. Stevens. 



Alfalfa.- A n exceedingly interesting and comprehensive bulletin concerning 

 flfa" has just appeared from the Xew York Experiment Stat.cn. Among 

 ll * subjects treated are the following: Varieties grown, uncongenial soil condition 



. Wkrt, F . A. F. C, On the investigations of Mr. A. H Bi.vu v «*""£ 

 ll0 » Ween intensitv of light and the length of illumination in &&****« 

 ^tures in seedlings of Avena saliva. Reprint from Proc Ron. Akad. 

 Amsterdam, Sept. 2 6, 1908. pp. 5. . _ _ 



* Wart, F. C, French, G. T., and SttM F. A., N. Y. A**, Ex P . Sta. 



U[ - 3fi. January, 1909. . u u . 



.. "Stewart, f . c> Frexch> g . t ., asd WltSOK, J. K., Tr-ubles of alfalfa 

 • ew Wk. N. Y. Am-ir. F.vn. Sta. Bull. w;. November, i9<*- 



