BUREAU OF CHEMISTR"^. 273 



the bacteria that occur upon the skin. It was also found that washing 

 the fish so as to remove the dirt and slime from their skin will delay 

 the invasion of the flesh by microorganisms. 



Department Bulletin 819, A Pink Yeast Causing Spoilage in 

 Oj'sters, was issued. 



The work upon oriental fermentations, especially the production of 

 soy sauce from soy beans, is being continued, and a paper has been 

 issued under the title Laboratory P^xperiments on the Manufacture 

 of Chinese Ang-Khak in the United States. A report on the identity 

 of AspergUlus oryzae is in press. 



The studies upon the fermentation of pickles and of sauerkraut 

 have been continued, and papers issued upon the pickle investigations 

 of the bureau and upon the control of sauerkraut production by ad- 

 justing the temperature, with reports of experiments. 



The process for producing vinegar from orange juice has been per- 

 fected, and two papers, one upon the production of orange vinegar 

 by the rapid process, the other upon the general subject of the manu- 

 facture of orange vinegar and upon its composition, are in press. 

 There is every indication that the production of orange vinegar is 

 establishing itself commercially as a small but valuable industry in 

 the orange-producing sections of California. Orange vinegar can 

 never, because of its cost, com])ete with cider or distilled vinegar, but 

 it can appeal to a discriminating trade because of its own merits and 

 characteristics. 



PLANT CHEMISTRY. 



A method for the determination of soil acidity has been published 

 under the title. Determining Soil Acidity and Alkalinity by Indica- 

 tors in the Field, and a paper on soil reaction and plant distriliution 

 is in press. In cooperation with the Bureau of Plant Indu^^trv, field 

 surveys have been made by this method which indicate that soil 

 reaction greatly influences the distribution of plants. These observa- 

 tions promise to be of great importance in ecology and in agriculture. 



There is in press a report which describes definitely the nature of 

 the odorous constituents of apples. Now that these substances are 

 known, it is possible to reproduce the flavor of apples by synthetic 

 means. In the course of this work, it was established that in respira- 

 tion apples give off acetaldehyde, a discovery of great significance in 

 plant physiology and probably also of practical importance in con- 

 nection with the storage of apples. 



Two papers were published on the constitution of capsaicin, the 

 pungent principle of capsicum, and one upon vaniliyl-acyl amides, 

 the series of compounds of which capsaicin is a member. These 

 amides show a definite pungency varying with the size of the mole- 

 cule. The rhomicnl constitution of capsaicin may now be considered 

 as settled definitely. The reconstituted substance is identical crystal- 

 lographically with capsaicin. 



A crystallographic study of the raphides and crystals of calcium 

 oxalate and other salts in' plant cells was begun, with the thought 

 that criteria might be obtained for the identification of plant ^issues 

 in food and drug products. It will be necessary to revise the crystal- 

 lographic and optical data on calcium oxalate, since this substance 

 has not been studied except superficially for 50 years or more. An- 



