82 ANNUAL REPORTS OF DEPARTMENT OF A{;RIC"ULTURE. 



The manufacture of citric acid, oils, etc., from waste citrus fruits 

 has been made the subject of a hiboratory investigation, mechanical 

 devices for lessening the cost of production have been planned, and 

 the results will now be tested by experiments on a commercial scale. 



In the Enological Laboratory economic studies in the utilization of 

 waste apples and grapes and the improvement of the by-products of 

 these crops are made. To this end the composition of American 

 grapes and apples in the different fruit districts of the country is 

 determined, and a critical study is made of commercial samples in 

 comparison with pure products of known history. The study of 

 yeasts and the preparation of pure cultures for practical use in 

 producing high-grade ciders, etc., is an important item in improving 

 quality. These yeasts were distributed to 13 of the chief fruit-grow- 

 ing States during the year for experimental use by persons interested 

 in the production of fruit by-products. A permanent laboratory 

 at Charlottesville, Va., and a field laboratory at Sanduslcy, Ohio, 

 make it possible to perform this work in a practical as well as a 

 scientific manner, insuring results of value to the growers and manu- 

 facturers. 



INSECTICIDES AND FUNGICIDES. 



The investigations to discover new insecticides and improve those 

 in use so that their efficiency may be increased and the injury to 

 trees and fruits diminished may well be included among the im- 

 portant economic chemical investigations, inasmuch as the saving 

 to the farmer, both in initial expense and in protection of the crop, 

 is enormous. Exhaustive investigations along this line have had 

 to do with the solubility of Paris green and lead arsenate in water, 

 involving 3,500 arsenic determinations; the problem of fumigation 

 with hydrocyanic acid gas, the results of the study, which are of 

 considerable economic importance, being already published as Part 

 III of Bureau of Entomology Bulletin 90; and the accumulation of 

 toxic compounds in the soil as the result of using poisonous ele- 

 ments, especially copper and arsenic, in sprays. A new phase of 

 this work, which should result in marked improvement of the com- 

 mercial insecticides and fungicides found on the market, is the 

 chemical and microscopic examination of these materials under the 

 insecticide act, which went into effect on January 1, 1911, and aims 

 to prevent the misbranding and adulteration of these commodities. 

 In connection with this work about 418 samples were examined, 

 involving some 2,800 determinations, the greater part of these being 

 made at the request of the Bureau of Entomology. The improve- 

 ment and discovery of suitable methods of analysis for the perform- 



