MABCH, 1920] PHYSIOLOGY 121 



Penicillin/it are the mos< abundant. In oulturing these fungi, Czapek's agar Beemed to be 

 the most efficient, as a greater number of forms grew on this medium. The various species 

 of fungi were inoculated into sterilized sugars and the amount of deterioration of the sucrose 

 was obtained. Unless the moisture content was reduced to a minimum there was considerable 

 deterioration, this varying with the different forms. A species of blue Aspergillus was not 

 only the most common in sugars but also caused the greatest deterioration. The spores 

 of this fungus contain invertase and can produce an inversion of the sucrose without the 

 development of mycelium. — C. W . Edgerton. 



820. Kopeloff, Nicholas, and Lillian Kopeloff. Some new phases of the problem 

 of preventing sugar deterioration. Louisiana Planter and Sugar Manuf. 62:237-238. 1919. — 

 Molds such as species of Aspergillus and Cladosporium occur in all sugar products causing a 

 deterioration, especially if the moisture content is high. Spores of some of these fungi contain 

 the enzyme invertase and a gum-forming enzyme. Consequently the presence of these spores, 

 even if they do not germinate, may result in a deterioration of the sugar. — C. W. Edgerton. 



821. Purvis, J. E. The conversion of saw-dust into sugar. Proc. Cambridge Phil. 

 Soc. 19: 259-260. 1919. 



ORGANISM AS A WHOLE 



822. Dtjfrenot, J. Les reactifs biologiques de l'espece et la specifite parasitaire. [Bio- 

 logical reagents and specific reactions of parasites.] Rev. Gen. Sci. Pur. et Appl. 30: 44-47. 

 1919. — A brief essay, based on recent papers by Stakman, Piemeisel, Peltier, Chapman, 

 Legrand, and others, showing that living organisms are the most delicate reagents of which 

 we now have any knowledge or control, certain parasitic bacteria and fungi distinguishing 

 not only between species with obscure characters but between varieties or strains in which 

 no distinguishing characters are visible. [See Bot. Absts. 2, Entry 1033.] — G. J. Peirce. 



GROWTH, DEVELOPMENT, REPRODUCTION 



823. Doncaster, L. Note on an experiment dealing with mutation in bacteria. Proc. 

 Cambridge Phil. Soc. 19: 269. 1919.— See Bot. Absts. 3, Entry 621. 



824. McCall, A. G., J. B. S. Norton, and P. E. Richards. Abnormal stem growth 

 of soybeans in sand cultures with Shive's three-salt nutrient solution. Soil Science. 6: 479- 

 481. PL 1, 2. 1918.— See Bot. Absts. 3, Entry 859. 



825. Salter, Raymond C. Observations on the rate of growth of B. coli. Jour. Infect. 

 Diseases 24: 260-284. 1919. 



MOVEMENTS OF GROWTH AND TURGOR CHANGES 



826. Engler, Arnold. Tropismen und exzentrisches Dickenwachstum der Baume. 

 Ein Beitrag zur Physiologie und Morphologie der Holzgewachse. [Tropisms and eccentric 

 growth in thickness of trees.] Preisschr. Stiftung Schnyder von Wartensee. 21: 1-106. 14 pi., 

 16 fig. Beer and Co.: Zurich, 1918. — Stout stems, as well as young twigs, of coniferous and 

 dicotyledonous trees are subject to geotropic bending. The latter arborescent plants are also 

 subject to heliotropic bending. In plagiotropic dicotyledons the eccentric growth on the 

 upper sides of branches and inclined stems- — regardless of convexity or concavity — is due to 

 gravitational stimuli, whereas eccentric growth of the undersides of branches and stems is 

 induced by longitudinal compression of the cambium. Longitudinal tension does not pro- 

 duce eccentricity. Not all portions of the stem are equally geotropic or heliotropic. "Hori- 

 zontal" eccentricity of branches occurs where the effects of gravity and compression neutralize 

 each other. The author devotes considerable attention to the study of the form of trees 

 growing on steep slopes and offers an hypothesis to account for the modus operandi of bending 

 in thick stems. [See Bot. Absts. 3, Entry 691.]— 7. W. Bailey. 



