96 PHYSIOLOGY [Box. Absts., Vol. VIII, 



659. KuiPER, K., Jr. Koolsuurbemesting nachtverlichting en andere groeibevorderende 

 facto ren in de plantenteelt. [Effects of carbon dioxide manuring, night illumination, and 

 other growth-stimulating factors upon plant culture.] Cultura 32: 332-344, 355-368. 1920. — 

 A general review is given of experiments on the above subjects done by various investigators. 

 The bibliography comprises 41 titles. — J. C. Th. Uphof. 



660. Reed, H. S. The nature of the growth rate. Jour. Gen. Physiol. 2 : 545-561. 1920. 

 — This paper is concerned with the application of the equation of an autocatalytic reaction 

 to the growth of shoots of 3 year old pears (Pyrus communis), seedlings of Juglans nigra, and 

 scions of Juglans regia grafted on Juglans nigra. The equation is applied also to data 

 obtained by Kretjsler on growth of maize as well as to data presented by Eckles and Swett 

 on the growth of Jersey heifers. The author finds a correspondence between the growth 

 rate and rate of an autocatalytic reaction, and considers that the growth of an organism 

 may be considered as a chemical reaction and that the growth rate for any moment is pro- 

 portional to the growth yet to be made. — L. Knudson. 



661. Saito, Kendo. Uber die chemischen Bedingungen der Askenbildung bei Zygo- 

 saccharomyces major Takahashi et Yukawa. [Chemical conditions for ascus formation in 

 Zygosaccharomyces major.] Bot. Mag. Tokyo 32: 1-13, 15-25. 1918.— It has been previously 

 shown that Zygosaccharomyces forms no spores when grown on the usual gypsum blocks; but 

 it has also been determined that on "soja bean sauce" with NaCl content of 5 per cent, and 

 suitable temperature, abundant asci with spores are produced in 5-12 days. The author now 

 shows that well nourished cultures produce a fine yield of asci and spores in 2-4 days on 

 gypsum blocks moistened with 0.5 dextrose and 4-10 per cent NaCl. Testing 73 substances, 

 including primarily inorganic and organic salts, carbohydrates, and certain amino acids, it is 

 found that many inorganic and some organic salts used in concentrations of 0.5-1.5 m., in 

 conjunction with 0.5 per cent dextrose, produce the same action; but in general non-elec- 

 trolytes are of no value, or of slight comparative value. Many neutral salts of metals were, of 

 course, toxic, and alkaline and acid salts often so in consequence of the reactions. — The 

 addition of relatively little acid or alkali to the NaCl-dextrose cultures causes inhibition 

 of the process, likewise all ammonium salts are inhibitory. Combinations of nutrient salts 

 are entirely favorable. In part at least the morphogenic stimulus in ascus formation is the 

 nutrient relation of the surrounding medium. — B. M. Duggar. 



MOVEMENTS OF GROWTH AND TURGOR CHANGES 



662. Bose, J. C. Researches on growth of plants. I, II. Nature 105: 615-617, 648-651. 

 Fig. 1-6. 1920.— The author discusses tropic movements in general, especially geotropism 

 and heliotropism. — 0. A. Stevens. 



663. RicoME, H, Action de la pesanteur sur les vegetaux. [The effect of weight on plants.] 

 Compt. Rend. Acad. Sci. Paris 171 : 261-263. 1920.— It is suggested that negative geotropism 

 may be due to the weight of the terminal portion of the plant causing a compression below 

 which stimulates growth and a tension above which retards it. This condition is indicated 

 by the longitudinal splitting of geotropically stimulated stems. It is thus concluded that 

 the plant exhibits a perception of weight. — C. H. Farr. 



664. Spruit, C. The influence of electrolytes on the tactical movements of Chlamydomonas 

 variabilis Dangeard. Recueil Trav. Bot. Neerland. 17: 129-204. Fig. 1-7. 1920.— Colloid 

 chemical representations can be made of the influence of chemotactic agents. With Chlamy- 

 domonas variabilis there was observed a clear positive geotaxy, whereas other investigators 

 have found C. pulvisculus to be negatively geotactic. Reaction to gravity ceases after add- 

 ing to the water small quantities of acid, base, or salt. The susceptibility to light, like that 

 to gravity, is diminished under the influence of added electrolytes. Besides a negative 

 phototactic reaction a positive reaction may also occur. Thigmotactic response is manifest 

 only in solutions which are not distinctly alkaline. — It was possible to produce an oxygen- 

 line in the dark under a cover glass. By means of Spirillum sp. it was shown that under the 



