322 PHYSIOLOGY [BoT. Absts., Vol. VIII, 



all be used in vegetative extension and can accumulate, with the result that the plant is 

 vigorous and fruitful. Finally, if nitrogen is still further reduced, carbohydrate reserves 

 accumulate in abundance but the plant is weak vegetatively and reproduces but little. The 

 role of other chemical elements and of water, light, temperature, and hereditary factors in 

 this problem are also doubtless important and should be thoroughly studied. The author 

 points out the importance in such a problem as this of obtaining a large body of chemical 

 analyses of the plants to be studied, made upon the various tissues and organs and at succes- 

 sive intervals during the year. — E. W. Sinnott. 



TEMPERATURE RELATIONS 



2190. Gericke, W. F. Influence of temperature on the relations between nutrient salt 

 proportions and the early growth of wheat. Amer. Jour. Bot. 8: 59-62. 1921. — Wheat seed- 

 lings were grown in the 126 3-salt solutions described by the committee on salt requirements, 

 and at 2 different temperatures, 28°C. (approximately the optimum) and 17°C. (considerably 

 below the optimum). It was found that the best growth at the lower temperature was pro- 

 duced when the proportion of potassium was high and of H2PO4 low; and at the high tempera- 

 ture when the proportion of potassium was low and of H2PO4 high. Temperature is thus 

 important as a factor in determining what are the mineral requirements for good germination 

 and initial growth in wheat. — E. W. Sinnott. 



2191. Hopkins, Fbederick Gowland. The effects of heat and aeration upon the fat- 

 soluble vitamine. Biochem. Jour. 14:725-733. Fig. 1-4 . 1920.— The experiments conducted 

 show that although fat-soluble A of butter displays considerable resistance to heat alone at 

 temperatures up to 120°C., it is readily destroyed by simultaneous aeration of the fat. — A. 

 R. Davis. 



2192. JoRGENSEN, I., AND Walter Stiles. Some scientific aspects of cold storage. Sci. 

 Prog. [London] 13: 614-620. 1919. — The authors outline some of the problems involved in 

 studying the cold storage of foods. Some changes which take place in stored fruits are dis- 

 cussed. — /. L. Weimer. 



2193. Winge, O. A practical form of thermostat aquaria heated by electricity. Compt. 

 Rend. Trav. Carlsberg Lab. [K0benhavn] 14": 1-4, 1920.— This form of thermostat 

 aquarium has been in successful use at this laboratorj^ for several years and has been of value 

 in giving aquatic organisms homogeneous conditions and in studying the effect of different 

 degrees of temperature on their activity. Heating units are placed underneath the tank and 

 these are insulated from the air. A mercury contact thermo-regulator operates a switch in the 

 heating circuit by means of a relay. The essential feature of this switch is a sealed glass tube 

 containing 2 drops of mercury connected electrically by the armature of the relay which 

 floats upon them; when the armature is raised contact is broken. An automatically operat- 

 ing air chamber for ventilation is provided. — F. Weiss. 



2194. ZiKEs, Heinbich. Uber den Einfluss der Temperatur auf verschiedene Functionen 

 der Hefe. [The influence of temperature on various functions of yeasts.] Centralbl. Bakt. 

 II Abt. 50 : 385^10. Fig. 5. 1920.— The budding activity of yeasts is more or less dependent 

 on those temperatures at which it was previously grown and to which it has adapted itself. 

 "Cold" yeasts, that is, yeasts formerly grown at low temperatures, show a much more rapid 

 growth (likewise more rapid ascospore formation) at all low temperatures than do cells of 

 the same species grown at a higher temperature, and conversely. Some yeasts are more 

 irritable in this respect than others. Cold yeasts adapt themselves more easily to higher 

 temperatures than high temperature yeasts to lower temperatures. The formation of fat 

 (in the fat granules) takes place very slowly at low temperatures (12-15°C.) and more rapidly 

 at high temperatures (20-30°C.). A secondary development of small fat globules occurs 

 very abundantly at low temperatures. Mycoderma cerevisiae is a weak glycogen former; 

 likewise Torula alba and Willa Anomaia. In Chalara imjcoderma variations in temperature 



