146 DEPAETMENTAL EEPORTS. 



necessary data to assist in the stndj- of the technique of cider, wine, 

 and vinegar fermentation, so tliat we may be better able to handle 

 the large amount of our fruits falling below merchantable grade, and 

 to determine the value of certain varieties for the manufacture of the 

 products mentioned. 



Second. The isolation and study of the organisms which cause fer- 

 mentation, both vinous and acetic, and also malfermentations which 

 tend to destroy the products sought to be secured and conserved. In 

 this study the prime data sought are the cliemical changes produced 

 in fermenting fruit musts or saccharine solutions of all kinds, and 

 the determination of the best methods of bringing about these chemical 

 changes in the most practicable manner, and conserving with certainty 

 the desirable products formed from further changes by reason of 

 malf ermentatioD . 



Under the first head, a considerable number of different varieties 

 of apples has been collected and analyzed during the year. This has 

 served for the beginning of a comprehensive study on the chemistry 

 of fruits. In the course of this preliminary work it has been found 

 that the methods of analysis are not well perfected, and as a conse- 

 quence it has become necessary to take up this whole subject anew. 

 This work will be continued on all our native fruits and berries which 

 have commercial inii)ortanco. 



Under the second head, a considerable number of alcoholic fer- 

 ments, belonging to the genus Saccharorayces, both from foreign wines 

 and ciders and those of American production, has been separated and 

 reduced to pure cultures. The study of these organisms as to their 

 chemical reaction on fruit musts and saccharine solutions is well 

 under way and promises most interesting scientific and economic 

 results. In the study of the alcoholic ferments proper, numbers of 

 organisms have been detected and isolated which are closely related 

 to the above-mentioned genus Saccharomyces, but which from the 

 nature of their reaction upon fruit musts are denominated malfer- 

 ments, because they destroy or injuriously alter those products which 

 it is desired to conserve. The critical study of these organisms awaits 

 a convenient time. 



This kind of work on fermentations is too new a field of investigation 

 to warrant a positive statement in regard to its importance, further 

 than to say that it is studied in Europe in the most assiduous manner 

 in the Government laboratories, and makers of wines, ciders, and vine- 

 gars assert that the laboratory results are used by them with the 

 greatest benefits. In the experiments in the use of pure cultures of 

 the alcoholic ferments at the Virginia Agricultural Experiment Sta- 

 tion most excellent ciders have been produced. 



There is a further application of this investigation, viz, the employ- 

 ment of these and allied organisms for the inversion of starch, in the 

 manufacture of commercial compressed yeasts, in the inversion of 

 nonfermentable sugars to fermentable forms, and in the differentiation 

 of sugars by the use of specific organisms brought to a state of pure 

 culture. This line of inquiry promises to ])e of great importance, both 

 in the chemical laboratory and in the practical application of chem- 

 istry to the arts and manufactures. 



MISCELLANEOUS INVESTIGATIONS. 



As in previous j^ears, the Bureau of Chemistry has been called upon 

 during the past fiscal year to make a number of analytical and other 



