222 EXPEETMENT STATION RECOED. 



Spraying with Bordeaux mixture has not proved satisfactory and this me lod 

 of control is no longer recommended. 



An account is given of the treatment of the college pond with copper sulphat*^ 

 for the destruction of algje which had become very troublesome in it. Treat- 

 ment of the pond with 1 part of copper sulphate to 4,000,000 parts of water 

 showed that after 24 hours there was a slight decrease in Anahwna (los-aquw, 

 the most common alga, and in 2 or 3 days it had practically disappeared. Spiro- 

 gyra, desmids, and diatoms appeared unaffected by the treatment, and the 

 animal life showed no ill effects, so far as the authors could observe. I'xom 

 examinations made of the bacterial content of the water it was found that there 

 was a rapid decrease for the first few days after treatment, after which there 

 was a slight increase, but that the number of bacteria per cubic centimeter of 

 water never reached the original proportion. 



A comparison of the numbers of bacteria in sterilized and unsterilized 

 soils, A. V. OsMUN {Massachusetts Sta. Rpt. 1905, pp. UfG-l^S). — A study was 

 made of sterilized soil to determine the effects of sterilization on the bacterial 

 flora. The stimulating effect of soil sterilization on plant growth had suggested 

 a similar effect on the bacterial content of the soil. 



To investigate this subject two boxes of equal size were filled with soil, one 

 being treated for half an hour with steam and the other left untreated. One 

 v,'eek after sterilization samples were taken from each box and the bacterial 

 content determined. At the first examination a decided decrease was noted in 

 the bacterial content of the sterilized soil as compared with the unsterilized, 

 but after an interval of 2 weeks the number of bacteria in the sterilized soil had 

 increased to almost double the number in the unsterilized soil and continued to 

 be greater as long as the investigation was carried on. 



From the results obtained in this experiment and from tests of other soils, 

 both sterilized and unsterilized, the author concludes that steam treatment of 

 soils stimulates bacterial development in them. 



Notes on the formation of albuminoid substances in plants, L. Monte- 

 martini (Atti 1st. Bot. Univ. Pavia, 2. sei:, 10 (1905). p. 20; abs. in Bot. 

 Centhl. 102 (1906), No. 28, pp. 35. .36").— From a review of the literature it is 

 shown that different investigators have obtained contradictory results regarding 

 the action of light on the formation of nitrogenous material in i)lants. 



The author carried on a series of experiments, a preliminary report of which 

 is given. From his results it is shown that in the germination of beans and 

 maize light exerts a very different effect, depending on the external and 

 internal conditions under which it acts. The results of the experiments are to 

 be given in detail at some future time. 



The stimulation of the nutrition of plants, H. Micheels (Rev. Hart. Beige. 

 32 (1906), No. 2, pp. 29-33; ahs. in Bot. Centhl, 102 (1906), No. 30. pp. 90. 

 91). — The author calls attention to the diverse conclusions of various investi- 

 gators relative to the effects of stimulants on the nutrition of plants, some 

 claiming that the addition of mineral fertilizers to the soil does not modify 

 the mineral composition of the plants, but only stimulates their growth and the 

 production of organic matter, while other investigators claim that certain min- 

 eral salts have a direct stimulating effect. 



The author, in connection with a physicist, investigated the effect of various 

 colloidal substances, and carried on experiments with barley, peas, buckwheat, 

 and oats, which show that colloidal solutions have a direct stimulating effect 

 and that in some cases they play the rol^ of diastases. This appears to open 

 up a new line of investigation on the nutrition of plants. 



