A. 1st—Because they deprive the blood of carbon, which is the chief cause of animal heat: and
2ndly—These gases coalesce into water, which greatly tempers the animal heat.
Q. Why do we feel lazy and averse to activity in very hot weather?
A. 1st—Because muscular activity would increase the heat of the body, by quickening the respiration: and
2ndly—The food we eat in hot weather, not being greasy, naturally abates our desire for bodily activity.
Q. Why do the inhabitants of tropical countries live chiefly upon rice and fruit?
A. Rice and fruit by digestion are mainly converted into water, and (by cooling the blood) prevent the tropical heat from feeling so oppressive.
Q. Why are poor people generally averse to cleanliness?
A. 1st—Cleanliness increases hunger; and as poor people are generally ill-fed, they are averse to cleanliness.