218 PHYSIOLOGY [Bot. Absts., Vol. IV, 



compounds, and that it must be looked at as the immediate cause of the loss of chlorophyll; 

 old leaves can be kept green by the addition of nitrogen fertilizer. It is also conceivable that 

 a great excess of nitrogen may lead to the decomposition of chlorophyll, and that shortage 

 of magnesium may act similarly. [See Bot. Absts. 2, Entry 574.] — H. C. Cowles. 



1443. Crocker, William. Distribution of dissolved oxalates in phanerogams. [Rev. of: 

 Molisch, Hans. Uber den microchemischen Nachweis und die Verbreitung geloster Oxalate 

 im Pflanzenreiche. Flora 11-12: 60-70. 1918 (See Bot. Absts. 2, Entry 577).] Bot. Gaz. 68: 

 72. 1919. 



1444. Crozier, W. J. Intra-cellular acidity in Valonia. Amer. Jour. Physiol. 49: 147. 

 1919. — Three cubic centimeters or more of liquid were extracted from the vacuole of a 

 single cell. In healthy cells the P H value was 5.9, which was not materially changed even 

 where the external reaction varied from P H 6.6 to P H 9.5. In death SO4 penetrates the cell 

 sap and increases the alkalinity to approximately that of sea water, P H 8.1. — Ernest Shaw 

 Reynolds. 



1445. De Vries, O. Invloed van verandering van tapvlak op latex en rubber. [Influence 

 of the change of tapping surface on the latex and rubber.] Arch. Rubbercult. Nederlandsch- 

 Indie 3: 130-138. 1919— See Bot. Absts. 3, Entry 2015. 



1446. Dodge, C. W. Tyrosin in the fungi: Chemistry and methods of studying the tyro- 

 sinase reaction. Ann. Missouri Bot. Gard. 6: 71-92. 1919. — A chemical study of the action 

 of tyrosinase, obtained from sporophores of Daedaha confragosa, Armillaria mellea, and 

 Polyporus svlphureus, shows that tyrosin is not deaminized in the tyrosinase reaction but 

 that the tyrosin molecule becomes more complex and the carboxyl groups are either split off 

 or masked in the resulting molecule. — S. M. Zeller. 



1447. Dowell, C. T., and P. Menoul. The action of furfurol and dextrose on amino- 

 acids and protein hydrolysates. Jour. Biol. Chem. 40: 131-136. 1919. 



1448. Duggar, B. M. The micro-colorimeter in the indicator method of hydrogen ion 

 determination. Ann. Missouri Bot. Gard. 6: 179-1S1. 1919. — An adaptation of the Dubosq 

 type of this instrument is described as admirably applicable for the testing of hydrogen ion 

 concentration of pigmented fluids obtainable in small quantities only. — S. M. Zeller. 



1449. Duggar, B. M., and C. W. Dodge. The use of the colorimeter in the indicator 

 method of H-ion determination with biological fluids. Ann. Missouri Bot. Gard. 6: 61-70. 

 Fig. 1 . 1919. — For each side of a complete Kober nephelometer-colorimeter there was arranged 

 a pair of cups slipping to a certain depth one into the other. On the left hand side the color- 

 less standard solution is used in the outer cup and the colored test fluid plus indicator in the 

 inner. On the right hand side the colored test fluid is placed in the outer cup and the standard 

 solution plus indicator in the inner. By this method difficulties in determining H-ion concen- 

 trations of colored solutions are largely overcome and the useful range of certain brilliant in- 

 dicators extended so that fewer indicators may be employed. — S. M. Zeller. 



1450. Falk, G. K. The carbohydrates of fresh and dehydrated vegetables. Jour. Indust. 

 Eng. Chem. 11 : 1133. 1919. — The results obtained indicate that no change in the carbohydrate 

 distribution as determined (such as a break down of the more complex to the simpler constit- 

 uents during dehydration) was observed. — Henry Schmitz. 



1451. Fennel, E. A., and M. A. Fisher. Adjustment of reaction of culture mediums. 

 Jour. Infect. Diseases 25: 444-451. 1919. — Bacteriologic culture media should be adjusted to 

 a definite hydrogen ion concentration and not by the method of titration to phenolphthalein. 

 The range of growth and that of optimum growth are given, in P H values, for various patho- 

 genic bacteria. — Schnan A. Waksman. 



