120 PHYSIOLOGY [BoT. Absts., Vol. X, 



anthocyan is accompanied by a decrease in the amount of organic acids. — Secondly, the rela- 

 tion of pigmentation and organic acids was studied in organs cut from the plant which pro- 

 duced them. In the 3 cases studied, corollas of Cobaea scandens, leaves of Ampelopsis tri- 

 cuspidata, and the hypocotyl axes of buckwheat, the formation of anthocyan was never 

 accompanied by an increase of acid. — /. C . Gilmmi. 



763. Minor, Jessie E. The reactions of cellulose. Paper 26: 584-5S7. 1920.— Data are 

 given to show that certain theories of the relation of dyes to cellulose are not tenable. — 

 H. N. Lee. 



764. Weimer, J. L., and L. L. Harter. Glucose as a source of carbon for certain sweet 

 potato storage-rot fungi. Jour. Agric. Res. 21: 189-210. 1921. — Fusarium acuminatum, 

 Diplodia tubericola, Rhizopus Tritici, Mucor racemosus, Sclerotium bataticola, Penidllium sp., 

 Botrytis cinerea, and Sphaeronema fimbriatian, all of which cause decays of sweet potato 

 {Ipomoea batatas), were grown on modified Czapek solution for 2 weeks at 28°C., a carbon 

 source being supplied by differing amounts of glucose. All the organisms except Sphaeronema 

 Umbriatum utilized glucose in considerable amounts. The amount of glucose actually con- 

 sumed at any concentration differed with the organism, and in general the greatest consump- 

 tion occurred in the weaker solutions (10 per cent), decreasing progressively with increasing 

 concentration. Five of the organisms grew in solutions containing 42-50 per cent glucose, 

 but Penidllium, sp. alone grew in a 58 per cent solution. — Dry weight of fungous material 

 varies with the species and with the concentration of glucose, for example, Botrytis cinerea 

 produced a maximum (1.0215 gm.) on 30 per cent glucose and Rhizopus Tritici a maximum 

 (0.4716 gm.) on 10 per cent. There is similar variation in the amount of glucose required to 

 produce 1 gm. of dry material. The "economic coefficient" for Mucor racemosus is greatest 

 (28.88) on 30 per cent solution and lowest (1.44) on 50 per cent solution, while for Rhizopus 

 Tritici it is greatest (17.67) on 50 per cent solution and least (3.70) on 10 per cent solution. — 

 Fusarium acuminatum, Sclerotium bataticola, and Sphaeronema jimbriatum affect the hydrogen- 

 ion concentration of the medium very slightly, while the remaining 5 organisms increase the 

 acidity appreciably. — All the fungi grow in solutions with maximum osmotic pressure varying 

 from 81.33 to 101.46 atmospheres. Fusarium acuminatum and Mucor racemosus show an in- 

 crease in total osmotic concentration, while the remaining fungi, in general, decreased the 

 concentration. — D. Reddick. 



765. WiTZEMANN, Edgar J. The law of probability applied to the formation of fats from 

 carbohydrates. Jour. Phys. Chem. 25: 55-60. 1921. — From data on the occurrence of the 

 various fatty acids in nature the author constructs a curve. This he considers from the 

 standpoints of probability, the general facts concerning fats in plants and animals, and the 

 2 general types of hypotheses dealing with the chemical steps in fatty-acid formation from 

 carbohydrates, as follows: (1) The fatty acids "are built up mainly from short carbon chains 

 (less than 6)." (2) "They are built up mainlj' from units of 6 carbon atom chains." The 

 author concludes that the evidence is in favor of the second hypothesis. — H. E. Pulling. 



METABOLISM (RESPIRATION, AERATION) 



766. Harter, L. L., and J. L. Weimer. Respiration of sweet potato storage-rot fungi 

 when grown on a nutrient solution. Jour. Agric. Res. 21 : 211-226. 1921. — The fungi included 

 in the study are: Fusarium acximinatum, Sclerotium bataticola, Diplodia tubericola, Penidl- 

 lium sp., Mucor racemosus, Botrytis cinerea, and Rhizopus Tritici. A modified Czapek solu- 

 tion, in which ammonium nitrate was substituted for sodium nitrate, and with the addition 

 of 10 per cent dextrose, was used as a culture medium. Penidllium sp., Botrytis cinerea, and 

 Sclerotium bataticola, which grew slowly, produced a maximum of more than 2 gm. of carbon 

 dioxide in 24 hours. The other organisms, which grew rapidly, produced a comparativelj'^ small 

 amount of carbon dioxide and reached their maximum soon after the culture fiask was inocu- 

 lated. The 3 slow-growing fungi produced a relatively large amount of dry matter and con- 

 sumed nearly all of the glucose; the reverse is true of- the remaining organisms. The quantity 



