30 EXPERIMENT STATIOX EECORD. 



current then inducing a depression, while the homodromous current induces 

 an enhancement of conductivity. 



Variations in respiratory activity in relation to sunlight, H. A. Spoehk 

 (Bot. Gaz., 59 {1915), No. 5, pp. 366-386, figs. iO).— This paper is a prefatory 

 announcement of a reaction believed to be caused by light through its effects on 

 the environment of the organism. 



Experiments described as carried out with onions, beetles, and (principally) 

 wheat seedlings are claimed to show that respiratory activity is greater during 

 the hours of sunlight, corresponding thus in a general way to the period of 

 atmospheric ionization. No increased respiratory activity could be obtained with 

 the artificial sources of light. 



On the function of chlorophyll, A. J. Ewabt (Proc. Roy. Soc. [ London], 

 Ser. B, 89 (1915), No. B 609, pp. Jf-i7).— Referring to the report published by 

 Wager (E. S. R., 31, 222), the author gives a general account of his own related 

 work to the present time. 



Results of studies described indicate that the assimilation of carbon dioxid 

 is not a simple process, but a very complex one, reversible in part, in which 

 at least the two pigments chlorophyll and xanthophyll and their derivatives 

 take part. Light supposedly influences the equilibrium between the reacting 

 substances and their products accelerating the tendency to oxidation on the part 

 of the pigments concerned. 



No peroxids are produced during the photo-oxidation of chlorophyll, xantho- 

 phyll, or carotin, but these substances, given light and oxygen, may act as 

 oxidases to themselves and to such substances as hydriodic acid, litmus, or 

 guaiacura. Some facts suggest that chlorophyll may be built up. not only from 

 ethyl chlorophyllid and phytyl alcohol, but also from xanthophyll and the prod- 

 ucts of tlie photo-oxidation of chlorophyll. 



Studies on the physico-chemical properties of vegetable saps. Ill, .T. A. 

 Harris, R. A. Gobtner, and J. V. Lawrence (Biochcm. Buh, 4 {1915), No. 13, 

 pp. 52-79, pi. 1). — This paper presents a portion of the data obtained in exten- 

 sion of a previous study (E. S. R., 31, p. 427). A comparison has been made of 

 the physico-chemical constants of the juices expres.sefl from the wall with those 

 from the included carpellary whorl in proliferous fruits of Pa,<i.<ii flora gracilis. 



It has been found that specific gravity, concentration, depression of the freez- 

 ing point, osmotic pressure, electrical conductivity, and mean molecular weight 

 are all su.sceptible to the influence of the environmental, and po.ssibly to the 

 physiological, state of the plant upon which they are borne. 



Fixation of ammonia by cell albumin, T. Bokorny {Bin}. Ccnthh. 35 {1915), 

 No. 1, pp. 25-30). — The author states that his previous conclusion?? (E. S. R.. 

 29, p. 30) have been confirmed. This supports the view that tobacco smoke 

 causes injury to plants largely through its content of ammonia, which belongs 

 to that class of compounds which are injurious to living protoplasm when 

 present in very small proportions on account of their ready combination with 

 the albuminous components of the cell. 



A study of delayed germination in economic seeds. D. H. Rose {Boi. Qaz., 

 59 {1915), No. 6. pp. Jf25-JtJf4. fid- D- — This is an attempt to discover some of 

 the problems, with their solutions, having practical interest for seedsmen and 

 growers. 



It is stated that hard-coated seeds of legumes and other seeds mentioned 

 germinate more rapidly after being blown against a bank of neetUe points. 

 Two varieties of lettuce seed improve in viability as they grow older, up to the 

 end of the fourth year at lea.st. This is thought to be due to an increased 

 permeability of the inner seed coat to water. 



