1905-6.] Miss I. D. Cameron on A Dietary Study. 335 
Cows are scarce in Japan ; dairy products are expensive, and can 
only be obtained by the wealthy classes. 
The Japanese eat less than Europeans, but their body- weight 
is considerably less. The studies of the diet of Japanese students 
will be considered later. 
Studies of the actual food consumption of communities in this 
country have been confined, so far as I am aware, to these 
investigations of the dietary of the working classes and of public 
institutions. There is an impression, which is steadily gaining 
ground, that the average amount of food consumed by the middle 
classes, where the factor of cost is not all-important as with 
labourers, is much greater than even the usual dietary standards. 
III. Present Investigation and Kesults. 
In order to determine the actual food consumed, a study 
was made of five residences for students in Edinburgh. Many 
of these students, especially those studying medicine, have 
a considerable amount of physical exercise while at work. A 
number also engage in athletics ; but, taken all round, one 
cannot say that students have what, as purely physical exertion, 
would be regarded as a moderate day’s work. The food require- 
ments of mental work have been studied by Atwater* with 
great care. A man was confined in a respiration calorimeter. 
The bodily waste was not found to be increased when the subject 
of the experiment diligently studied a German scientific book. 
It has been suggested that, since the nervous system contains 
8 per cent, of fatty material, much fat is necessary in mental 
work.f Leaving the difficulty of digestion of fats out of con- 
sideration, the absence of appreciable bodily waste during hard 
study makes this view untenable. Other popular theories are 
that fish and phosphorus are direct mental stimulants, but 
these are not founded on scientific facts. The truth seems to be 
that easily digested food is best for those engaged in brain-work. 
The digestion of a heavy meal entails an expenditure of nervous 
energy, and the blood-supply to the brain is interfered with by 
the increased supply to the digestive organs. 
* U.S. Department of Agriculture, Bulletin 44, 1897. 
t Referred to by Yeo, in Food in Health and Disease. 
