730 EXPERIMENT STATION RECORD. 



seeds of A. pycnantha which have been dried in air contain 4.5 per cent ol 

 nitrogen, while those with the testa removed show 5.5 per cent, this component 

 being present partly as protein and partly as various other organic compounds. 

 Percentages of nitrogen obtainable by different methods are given. 



It is stated that with Sorensen's method of titration no fixation of formal- 

 dehyde by amino groups occurs. Attempts to isolate amino acids invariably 

 resulted in the discovery of traces thereof. The amount of purin nitrogen pres- 

 ent is said to be less than 1 per cent. 



The action of radium and radio-activity on germination in the higher 

 plants, H. Agxjlhon and Th^r^se Robekt {Ann. Inst. Pasteur, 29 (1915), So. 6, 

 pp. 2G1-27S). — The authors have made a study of the effects of radio-activity on 

 seeds during the i)eriod in which the young plants are living on the reserves 

 contained in the seed. 



Peas were used in three series of experiments. In the first, they were ex- 

 posed to such emanations as could traverse the walls of sealed tubes of thin 

 glass containing radium bromid. In the second, the seeds were germinated in a 

 solution containing radio-active material. In the third, the emanation was per- 

 mitted to diffuse from the radium directly into the space containing the seeds. 



In the first series, the observable action was unfavorable to development. 

 In the second, the slight concentrations employed appeared to be ineffective. 

 In the third, an accelerating effect on early growth was noted, associatetl with 

 a degree of etiolation. The possibility that ozone production may have been a 

 factor in the last mentioned case is discussed. 



Rules and mechanism of inhibition and correlation in the regeneration of 

 Bryophyllum calycinum, J. Loeb (Hot. (laz., 60 (1915), No. 4. pp. 2.',9-276. figs. 

 j,1). — The plieiiouiena of inhibition of regeneration have been studietl in B. caly- 

 cinum, and it is stated that they follow the rule that if an organ inhibits re- 

 generation or growth in another organ the latter often accelerates and favors 

 regeneration in the former. This is interpreted to mean that the inhibiting 

 organ receives something from the inhibite<l organ which is necessary for re- 

 generation. 



It is pointed out that this view is in harmony with the older assumption that 

 the phenomena of inhibition in regeneration, and of correlation, may be at- 

 tributed to the How of ni;iterial and to the block thereto after mutilation. 



The determination of additive effects, W. J. V. Osterhovt (B(jt Gnz., 60 

 (1915), No. 3, pp. 228-234, figs. 4). — Having pointed out in previous papers (E. S. 

 R., 31, p. 627; 32, p. 223) tliat in measuring antagonism it is of importance 

 to determine the additive effects of the substances employed, the author gives 

 analyses of typical cases. He concludes that in most cases two solutions which 

 are equally toxic remain so (at least approximately) wlien both are diluted 

 to the same degree, allowing the additive effect to be easily determined. In 

 exceptional cases where this does not hold a value may be assigntnl to the 

 additive effect. Similar considerations apply to unequally toxic solutions. 



Acid accumulation and destruction in large succulents, E. R. Long (Plant 

 ^rorl(1, 18 (1915), No. 10, pp. 261-272, fig. 1).—In these experiments, the inves- 

 tigations of Richards (E. S. R., 30, p. 429; 32, p. 429) have been extended to 

 include the larger succulent cacti Ecliiuocactus trislizcni nndCarncpi^a gigantca. 



It was found that the acidity of the sap of these cacti was higher in the early 

 morning than at sunset, probably on account of nocturnal metabolism and of 

 daily high temperature and photolysis. The lugher acidity present in the 

 early morning in the outer portions is thought to be relateil to the concen- 

 tration of sugar in this region. The comparative protection given to the inner 

 portions, as regards heat and light, is attributed to the lesser diurnal differences 



