CHEMICAL SCIENCE. 237 



impurities. When too much heat is applied, the filtering or straining opera- 

 tion will be imperfectly accomplished. Instead of using sand as the strain- 

 ing or filtering medium for the gas, clay and earths of most kinds may be 

 employed, as also chalk, gypsum, lime, black oxide of manganese, some 

 salts, plumbago, charcoal, etc. 



OX THE rRESEXT STATE OF CHEMICAL KNOWLEDGE IX RELATION 

 TO ALCOHOLIC BEVERAGES AND THEIR FALSIFICATIONS. 



At a recent meeting of the Boston Society of Natural History, Dr. A. A. 

 Hayes, by request, addressed the Society on the above subject. 



He stated that the products of fermentation whether resulting from 

 " worts," in which the altered starch of grains furnishes the material, or the 

 " must " of expressed juices of grapes, fruits and plants might be, for con- 

 venience, classed as wines. Thus ale, which is the product of the first fer- 

 mentation of malted barley, may be considered as a wine of malt; the 

 addition of hop extract being a matter of taste, which replaces the fruit 

 extract in wines. If we include also the mixtures of cane products, sugar 

 and water, honey and water, and, finally, skimmed milk, we have sources of 

 various resorts for producing exhilaration or intoxication, adopted by all 

 nations. 



The first chemical change in many of the mixtures used is produced by the 

 remarkable body called diastase, which has the power of converting nearly 

 two thousand times its own weight of starch into dextrine, or about half that 

 quantity into grape sugar. This body is developed in the act of germination 

 in grains and seeds ; and probably in this principle of malted barley we have 

 the type of a class of these substances, which in different ways act to produce 

 remarkable transformations in organic bodies. 



The second change, which demands attention, is that of the conversion of 

 dextrine and glucose the sugar of fruits into alcohol, which remains dis- 

 solved in the fluid. This breaking up and rearranging of the elements of 

 sugar, is effected, as is well known, through the aid of the beer yeast plant, 

 usually. Like diastase, the beer yeast plant is endowed with life, and has 

 the power of communicating motion to organic and organized matter, result- 

 ing in change of composition. In so simple an expression of the phenomena 

 of beer, or wine production, we have omitted some most important sub- 

 stances, which participate in the changes. These are the natural fixed oils 

 and fats, and the volatile odorous bodies in grains, but more especially in 

 grapes, fruits, cane products, etc. Thus the hop extract, added before fer- 

 mentation to ale, beer, or porter, becomes altered, as do the grape oils ; and 

 the remark applies to all known cases of fermentation of mixed solutions. 

 Mature grapes contain a natural ferment, in its appropriate cells, requiring, 

 to bring its affinity in view, only that the cell walls and tissues of the fruit be 

 broken, so as to provide fluid sugar, on which it reacts. Fermentation, 

 which at a temperature of 70 F. commences immediately in grape juice, 

 develops, besides alcohol, a whole class of new bodies. So in the fermen- 

 tation of grains, the fixed bland oils of the seeds, slightly altered, remain, 

 while more volatile odorous oils are directly produced from materials present. 

 Xow these oils deserve special attention, because on the production of these, 

 and their subsequent further change, the money value of the beverages 

 depends. A very large consumption of beverages is supplied by the first 



