582 ANNUAL REPORTS OF THE DEPARTMENT OF AGRICULTURE. 



tectioii ()f small quantities of quiiiin in bittors containing chinchona 

 alkaloids has been studied, and the nioditied thalleoquin reaction 

 was found to be capable of detecting as low as one one-hundredth of 

 a milligram of quinin. 



OTHER LABORATORIES. 



BurrALO laboratory. — During the j'enr 147 samples of imported 

 foods and drugs were submitted to this laboratory by the ])orts 

 assigned to its jurisdiction. Confei-ences have been held with dealers 

 and manufacturers regarding the labeling of their products and in- 

 spections made of factory methods. A method for the determination 

 of milk solids in milk chocolate, especially for the estimation of 

 casein, has been modified after an examination of 24 samples of coco 

 butter. Various methods for the determination of fat in dried milk 

 have been tried with some better success than last year. In the study 

 of grape juice it was found that when cane sugar Avas added to the 

 juice, in a few days much of the sucrose was changed to invert sugar, 

 and after a month all of it was so inverted, thus making it prac- 

 tically impossible for an analyst to state positively from his sugar 

 determinations only that sucrose had been added to the juice. 



Cincinnati laboratory. — In addition to the analysis of regular 

 samples, hearings and routine investigations were made of the milk 

 supply of Cincinnati and of the method of manufacture and the 

 chemical properties of maraschino and maraschino cherries. 



Dejs'ver laboratory. — The studies of commercial vanilla extracts 

 have been continued, a special effort having been made to determine 

 the limits of composition of extracts made according to the United 

 States Pharmacopoeia formula, with particular reference to the va- 

 nillin content, color value, and the so-called lead number. A prac- 

 tical method has been devised for determining minute quantities of 

 coumarin in the presence of vanillin. (See Circular 95, Bureau of 

 Chemistry.) A promising method for the determination of the 

 amount of oil of peppermint in alcoholic solutions, making use of 

 the refractometer, has been devised. In collaboration with other 

 bureau laboratories studies have been made on the composition of 

 berry fruits sold in the Denver market. 



Honolulu laboratory. — The principal work was on oriental im- 

 ports. Particular attention was given to the labeling of Chinese and 

 Ja]janese diTigs as to alkaloidal, alcoholic, and acetanilid content, 

 and to the use of coal-tar colors in food products. 



Kansas City laboratory. — A considerable amount of investigation 

 was undertaken on flour bleached with agents other than nitrogen 

 peroxid, and some valuable preliminary results obtained. This work 

 will, however, have to be greatly extended before definite conclusions 

 can be drawn. 



New Orleans laboratory. — A few of the Italian importers of New 

 Orleans have been adding about 30 per cent of cottonseed oil to their 

 imported olive oil after it has passed the inspection of this laboratory 

 and selling it locally as pure olive oil. Since the discovery of this 

 practice all olive-oil importations have been reported to the State food 

 commissioner as soon as the inspection by this laboratory is completed. 



Omaha laboratory. — During the months of July, August, and Sep- 

 tember, 1911, the regular force of this laboratory with additional as- 



