398 



W. Dörries: Chemische Physiologie 1915 und 1916. [42 



in the geueral proccsses of plant metabolism. 2. Chemical analyses showed 

 tliat ethylene caiised the simple sohible substauces to increase at the expense 

 of the higher soluble and insoluble forms. a) The hot alcohol-ether soluble 

 ßubstances (sugars, amino acids, amids, Polypeptides, Hpoids etc.) increased 

 by 8 — per cent, while the insoluble substances (proteins, starch, cellulose, 

 lignocellulose, etc.) were correspondingly diminished. The water content of 

 the ethylene treated and control tissues was the same. b) The lower soluble 

 ßugars (by direct reduction) wäre about 11 per cent more and the higher 

 soluble sugars (by reduction after hydrolysis) about 3 per cent less. The 

 reducing power of the alcohol-ether insoluble residue, after hydrolysis, was 

 decidedly less for the ethylene treated tissue; also, the cellulose content was 

 diminished by about 3 per cent. c) Amino acid plus amids were more, and the 

 Polypeptides apparently less in the ethylene treated tissue. The protein 

 content also was about 3 per cent less. d) Fats were much less abundant in 

 the treated tissue. The free fatty acid value was unchauged. 3. The acidity 

 of the ethylene treated tissue was not found to be changed. 4. Ethylene caused 

 an increase of osmotic pressui-e, as measured both by the freezing point and 

 plasmolytic methods. 5. The permeability was not sharply affected by the 

 ethylene, although it was somewhat increased. 6. Ethylene affected respi- 

 ration, retarding both the COg production and the O2 absorption, but the 

 respiratory ratio remained practically the same. An exception to the preceding 

 Statement was found in the case of the shortest exposure period (3 hours), 

 in which there occurred. apparently. an excessive production of CO2. thereby 

 increasing the ratio." 



456. Hasselbring', H, aud HaAvkius, L. A. Physiological changes 

 in sweet potatoes during storage. (Journ. Agr. Res V, 1915. p. 331 

 bis 342.) - Ref. in Bot. Centrbl. CXXIX, 1915, p. 294-295. 



457. Hasselbring-, H. and Hawkins, L. A. Carbohydrate trans- 

 formations in sweet potatoes. (Journ. Agric. Res. V, 1915, p. 543 

 bis 560.) - Ref. in Bot. Centrbl. CXXXV, 1917, p. 367. 



458. Heiiiricher, E. Über den Mangel einer durch innere Be- 

 dingungen bewirkten Ruheperiode bei den Samen der Mistel 

 ( Viscum album). (Sitzb. Akad. Wien, Math.-Naturw. Kl., Abt. I. CXXV, 



1916, p. 163-188.) - Ref. in Bot Centrbl. CXXXIV, 1917. p. 312-313. 



459. Herzfeld, E. und Klinger, R. Quantitative Untersuchungen 

 über den Indol- und Tryptophanumsatz der Bakterien. (Centrbl. 

 Bakt., I. Abt., LXXVI, 1915, p. 1-12.) - Ref. in Bot. Centrbl. CXXXV, 



1917, p. 379. 



460. Jacoby, M. Über Harnstoffspaltung durch Bakterien. 

 (Biochem. Zeitschr. LXXIV, 1916, p. 109-115.) - Ref. in Bot. Centrbl. 

 CXXXIV, 1917, p. 54-55. 



461. Janke, A. Die Säuerung des Äthylalkohols durch Essig- 

 bakterien. (Centrbl. Bakt., II. Abt., XLV, 1916, p. 534-547.) - Ref. 

 in Bot. Centrbl. CXXXIV. 1917, p. 267. 



462. Klebs, G. Über Wachstum und Ruhe tropischer Baum- 

 arten. (Jahrb. wiss. Bot. LVI, 1915, p. 734-792.) - Ref. in Bot. Centrbl. 

 CXXIX, 1915, p. 437. 



463. Klebs, G. Zur Entwicklungsphysiologie der Farn- 

 prothallien. (Sitzber. Akad. Heidelberg, Math.-Natiirw. Kl., Abt. B, 1916, 

 p. 82.) - Ref. in Centrbl. Biochem. Biophysik XIX, 1917, p. 12-14. 



