126 CHEMICAL, MEDICAL AND DIETICAL PROPERTIES. 



their botanical origin and yet all instinctively used for 

 the same purpose, by remotely situated nations, for the 

 production of useful, agreeable and refreshing beverages. 

 By taking the normal temperature of the human body 

 at 98, it follows that where food is taken into the stomach 

 of a lower temperature than that of the body it must 

 necessarily abstract heat from the stomach and surround- 

 ing tissues, so that where the practice of taking cold 

 food becomes habitual depression occurs and the 

 stomach is consequently disordered, and the system 

 must make good this heat lost in raising the temperature 

 of cold food or else suffer. The body demanding food 

 when in an exhausted state, cold food or drink makes an 

 immediate drain upon the system for heat before it can 

 supply material for producing combustion, and the body 

 is thereby taxed to supply heat at a time when it is least 

 fitted for it. It is natural, therefore, that there should be 

 a craving for warm food, and as liquid food is deficient 

 in beat-giving matter, the use of cold drink is more 

 injurious than that of cold food. From other experiments 

 it appears that the introduction into the stomach of three 

 or four grains of theine, which is the quantity contained 

 in the third of an ounce of good tea, has the remarkable 

 effect of diminishing the daily waste or disintegration of 

 the bodily tissues which may be measured by the quantity 

 of solid constituents contained in the many secretions, and 

 if such waste be lessened the necessity for food to repair 

 that waste will obviously be decreased in corresponding 

 proportions. In other words, says Professor Johnstone, 

 " by the consumption of a certain quantity of tea daily the 

 health and strength of the body will be maintained to an 

 equal degree upon a smaller supply of ordinary food." Tea, 

 therefore, saves food ; stands to a certain extent in place 

 of food, while at the same time it soothes the body and 



