O'SHEA — ASPECTS OF MENTAL ECONOMY. H 



"Hence, in reference to nutrition, we may say that tea increases 

 waste, since it promotes the transformation of food without supplying 

 nutriment, and increases the loss of heat without supplying fuel, and 

 it is therefore especially adapted to the wants of those who usually 

 eat too much, and after a full meal, when the process of assimila- 

 tion should be- quickened, but is less adapted to the poor and ill-fed, 

 and during fasting." 



His experiments with coffee show an influence similar in a 

 way to that of tea. He says i 1 



"Of twenty-three experiments on myself and others there was from 

 half an ounce of coffee an increase in the quantity of carbonic acid 

 evolved of 0.98, 1.02, 0.9, 0.4, 1.16 and 2.54 grains per minute at dif- 

 ferent times, whilst the quantity of air inspired was increased 40, 34, 

 35, and 84 cubic inches per minute with the same experiments. Three- 

 quarters of an ounce of coffee did not give a greater increase, but 

 the actual increase was 0.68 and 1.68 grain of carbonic acid and 28 

 and 54 cubic inches of air per minute. 



"The conditions, therefore, under which coffee may be taken are 

 very different from those suited to tea. It is more fitted than tea 

 for the poor and feeble. It is alsb more fitted for breakfast, inas- 

 much as the skin is then active and the heart's action feeble; whilst 

 in good health and with sufficient food it is not needful after dinner, 

 but if then drank should be taken soon after the meal. Hence in 

 certain respects tea and coffee are antidotes of each other, and we 

 know that they are now taken indiscriminately, although in a chief 

 action they are interchangeable. 



"Coffee is an excitant of the nervous system, but not in the same 

 degree as tea. It produces sleeplessness in many persons when it is 

 taken at night, probably by exciting the heart's action, and preventing 

 that fall which is natural at night, and requisite to permit sound 

 sleep. I do not think that there is the same degree of reaction after 

 taking strong coffee as follows strong tea. It is needless to add, that 

 none of these effects may be marked if the infusion be very weak, 

 as is common among the poor, and in this respect it resembles very 

 weak tea." 



I am not familiar with the results of experiments relating 

 to the influence of cocoa; but it is known that its active prin- 

 ciple, theobromine, resembles the active principles of tea and 

 coffee, theine and caffeine, and it is probable that its action in 

 the system is somewhat like these. 



J Op. cit., pp. 365-367. 



