FOODS — HUMAN NUTRITION. 165 



Studies of the chemical composition of hot and cold Avater infusions of sev- 

 eral types of coffee revealed the fact that cold water extracted from coffee the 

 same weij^ht of materials as boiling water, but the cold water Infusion is some- 

 what less palatable than the latter. There was little chemical difference be- 

 tween them, and the physiological effect of the cold water extract of coffee was 

 presumably the same as a hot water infusion, except for esthetic considerations. 

 According to the report, " it is probable that cold water fails to extract certain 

 oily bodies or fats which contribute attractive taste and aroma. The total 

 extract is frequently higher in cold than in hot water. . . . Cold water ex- 

 tracts from tea only IT.-'j per cent of its total caffein, while from coffee it ex- 

 tracts the whole. Similarly, cold water extracts from tea 13 per cent of its 

 total tannin, while coffee under the same treatment yields practically the whole 

 of its caffetannic acid." 



An infusion of unroasted coffee has a disagreeable taste, the roasting process 

 being necessary to render the coffee palatable. The chemistry of roasting con- 

 sists largely of a caramelization process, with the formation of certain oils and 

 aromatic principles. Little caffein is lost in the process, but the amount of 

 caffetannic acid is diminished considerably, a greater reduction taking place in 

 the preparation of the "high roasted" coffee than in the "pale roasted" 

 coffee. 



In this investigation no relation could be traced between the esthetic quality 

 of coffee and the chemical composition of the infusions. No important differ- 

 ence in the amount of caffein was found between the common and the finest 

 varieties. The flavor, body, and aroma of the coffee are probably due to small 

 amounts of oil bases or aromatic principles which are formed during the roast- 

 ing process. The esthetic quality of coffee depends in a great degree upon the 

 care spent in the roasting process. Pyridiu was also found, but not in suffi- 

 cient quantities to estimate. 



From these observations, the following conclusion as to the food value of 

 coffee is drawn : " The infusion of coffee presents practically very little mate- 

 rial that Is of direct nourishing value, but by diminishing nervous fatigue, by 

 virtue chiefly of the caffein present, it may increase muscular power. It is 

 not itself a builder of tissue. The use of coffee after dinner, it is of interest to 

 note, is justified in a large number of cases by the fact of its stimulating effect 

 upon the vital centers, and it is said to serve to some extent as an antidote to 

 alcohol. It is commonly claimed to remove drowsiness; as a matter of fact, in 

 many subjects it produces drowsiness, but this is usually followed quickly by 

 marked wakefulness. The practice of drinking coft'ee after a meal for the sake 

 of the stimulus which is experienced has much to be said in its favor dieteti- 

 cally. There is no reason for supposing that coffee possesses any value as a 

 food." 



On the compcteition of the essence of coffee — the presence of pyridin, G. 

 Bertrand and G. W. Weisweiller {Bui. Sci. Pharmacol., 20 {1913), No. 12, pp. 

 705-707). — In several samples of freshly roasted and ground coffee amounts of 

 pyridin were found, varying from 200 to 400 mg. per kilogram. Experiments 

 were carried out which would indicate that the aroma of coffee is due to 

 pyridin. Methods of analysis are described, and the suggestion is advanced 

 by the authors that pyridin may possibly play an appreciable role in the physio- 

 logical effect of coffee infusion. 



Commodities and provisions {Ann. Statis. Paris, 32 {1911), pp. 242-S06). — • 

 Statistics are given regarding the meat trade, dairy products, eggs, grains, and 

 other food supplies entering into commerce. 



