626 EXPERIMENT STATION" RECORD. [Vol.36 



color were exposed to atmospheres of pure carbon dioxid and of atmospheric 

 air so diluted with carbon dioxid that the mixture contained from 5 to 25 per 

 cent of oxygen. 



The roots of the species were found to maintain a feeble growth rate in an 

 atmosphere containing as little as 5 per cent of oxygen, but growth stopped in 

 both species in pure carbon dioxid. Recovery from the asphyxiation occurred 

 sooner in Prosopis than in Opuntia and in both sooner at high than at low 

 soil temperatures. The results are believed to indicate that the response of the 

 roots of Opuntia to a diminished oxygen supply, such as occurs with increasing 

 depth below the surface of the ground, is a contributory factor in bringing about 

 the superficial placing of roots. 



The embroyo sac and pollen grain as colloidal systems, F. E. Llotd (Mem. 

 N. Y. Bat. Gard., 6 {1916), pp. 561-563) .—The author reports very briefly on 

 certain observations made on the behavior of protoplasm, which is recognized 

 as a hydrophile emulsion colloid, showing alterations corresponding to changes 

 in water content and space relations of the dispersoids and the disperse medium. 

 He admits that it is not possible at the present stage of knowledge to discount 

 the views of Borowikow (E. S. R., 33, p. 28) that the agents concerned in 

 swelling are also concerned with growth, since we do not yet know how swell- 

 ing, shrinking, and coagulating reagents affect the relation of change of hydra- 

 tation to the capacity of protoplasm to secrete and to hold water within the 

 vacuoles, the solutions, suspensions, etc., of which are unknown but complex as 

 regards composition and behavior. 



Contents of amylase in ripening seeds of horse beans, A. Blaqovieshchen- 

 SKii (Blagoveschtschenski) {Znhr. Russ. Fiz. Khim. Obshch., ChaM Khun., 

 47 {1915), No. 6, pp. 1529-1532; abs. in Jour. Chem. Soc. [London^, 110 (1916), 

 No. 639, I, p. 109). — It was found that in seeds of Viola faba minor the amount 

 of amylase present corresponded approximately to the rate of starch accumu- 

 lation. This is considered as evidence of the synthesizing action of amylase in 

 the ripening seeds, the lack of complete parallelism being attributed to the loss 

 of some of the starch from the assimilatory organs. 



Present status of the problem of the effect of radium rays on plant life, 

 C. S. Gageb {Mem. N. Y. Bat. Gard., 6 {1916), pp. 153-160.)— The evidence is 

 here briefly reviewed, as obtained by various investigators including the author, 

 since the publication of his previous summation of the known related facts 

 (E. S. R., 20, p. 1124). It is considered to justify the broad inference that 

 although radio-activity may act as a stimulation to plant growth, our present 

 knowledge regarding the cause and the effects of that agent warrants little, if 

 any, hope of its profitable utilization in practical agriculture. 



The influence of ultraviolet rays on phosphorescent bacteria, F. C. Gerret- 

 SEN {Centbl. Bakt. [etc.], 2. Abt., U {1915), No. 17-23, pp. 660, 66i).— Reporting 

 the results of some preliminary experiments, the author states that Photo- 

 bacterium phosphorescens exhibited luminosity and the function proper to 

 catalase for several hours after being killed by means of ultraviolet rays. 



The influence of inorg-anic salts on the development of Actinomycetes, III, 

 F. MtJNTER {Centbl. Bakt. [etc.'], 2. Abt., U {1916), No. 2^-25, pp. 673-695, 

 figs. 9). — Continuing previous work (E. S. R., 31, p. 324), the addition of 5 

 per cent of potassium chlorid, sodium chlorid, potassium nitrate, and sodium 

 nitrate to nutritive media was found to increase growth markedly, but de- 

 creased spore formation in Actinomycetes. The addition of 10 per cent arrested 

 development in nearly all cases. The corresponding salts of magnesium hin- 

 dered growth, and magnesium carbonate arrested it completely. Spore forma- 

 tion was increased by small but decreased by larger additions of the chlorids, 

 nitrates, and carbonates of calcium, barium, and strontium, the carbonates, 



