320 TlMEHRI. 
heavy meal could be taken about 3 o'clock or so in the 
afternoon, and a light meal later on in the evening, but 
not too near bed time. For those who have much mental 
work in the later part of the day the heavy meal may 
with advantage be deferred till the evening, but 8 
o'clock p.m., is much too late. In addition to the water, 
and as supplementing it to a greater or less extent, 
artificial beverages are made and used by man, the 
principal being tea, coffee and cocoa. They are useful 
as being in small doses nerve stimulants and so removing 
the sense of fatigue after work, When taken hot as 
they usually are they a6l with benefit on the skin. 
Opium and tobacco and some allied substances are eaten 
or smoked, and though not food are largely used by 
nearly all the world. Tobacco and opium are perhaps 
the least harmful of many that are used. The reason 
for their use is somewhat indefinite, partly no doubt 
custom influences this matter, but they are all nerve 
sedatives. Nevertheless we can well affirm that they 
are not necessary to health, and that if their use is 
not kept within relatively small limits like alcohol 
they are positively injurious either mentallv or physi- 
cally. Alcohol and its use as an article of food 
will not require much notice here. No doubt it has 
its uses but it cannot be too strongly asserted that in a 
condition of health it is not required, that positively 
nearly all are better without it and that ninety-nine 
persons out of a hundred who take it in the firm belief 
that they require it are self-deceived. The diseases 
produced by errors in foods are many, and can be shortly 
indicated here as being produced by excess or defect in 
quantity and quality of the whole or of any part of the die- 
