. Biological effects of radiation; mechanism and measurement of radiation, applications in biology, photochemical reactions, effects of radiant energy on organisms and organic products. Radiation; Biology. 652 BIOLOGICAL EFFECTS OF RADIATION he also observed a diminution of granular size and to this, rather than to lowered viscosity, he attributes the change in Brownian movement. With Amoeba rostock, he likewise found increased Brownian movement. Forbes and Thacher (102) treated the eggs of an annelid, Nereis, with beta rays of radium. They then fertilized the eggs and centrifuged them. Irradi
. Biological effects of radiation; mechanism and measurement of radiation, applications in biology, photochemical reactions, effects of radiant energy on organisms and organic products. Radiation; Biology. 652 BIOLOGICAL EFFECTS OF RADIATION he also observed a diminution of granular size and to this, rather than to lowered viscosity, he attributes the change in Brownian movement. With Amoeba rostock, he likewise found increased Brownian movement. Forbes and Thacher (102) treated the eggs of an annelid, Nereis, with beta rays of radium. They then fertilized the eggs and centrifuged them. Irradiated eggs showed somewhat less viscosity than controls. It may be noted that the centrifuge method is an excellent check on the Brownian movement method of determining viscosity, and vice versa, for if protoplasmic granules decrease in diameter, their Brownian move- ment would be accelerated, whereas their movement under the influence of centrifugal force would be greatly retarded. â â Aa. fc ii jLi^iMi a. Fig. 3.âThe effect of mild radium treatment on the viscosity of cells of Spirogyra varians. {After Feichtinger, 197.) (a) Control cells. No displacement of chromato- phores by centrifuging. (6) Cells exposed to beta and gamma rays from RaBr2 prepara- tion of 4 mg. radium equivalents. Chromatophores almost completely displaced by same centrifuge treatment as used on control (3a). (c) Cells treated with alpha rays from polonium preparation of mg. radium equivalents. Same time of centrifuging as in 3 a, h. Rochlin-Gleichgewicht (317) exposed cells of Elodea and Ptery- gophyllum to radium emanation and found first an increase in rate of streaming and then a decrease. The results were interpreted as indicat- ing first a decrease of protoplasmic viscosity, and then after longer or stronger dosage, an increase. The work of Rochlin-Gleichgewicht is of considerable interest and will be discussed further below. Feichtinger (97) centrifuged Spirogyra cells following exposure to
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