XII Indulgence in narcotics, opium, chloral, chlorodyne, ether, absinthe, and all others of the class, is an entire departure from natural law. Except under the direction of skilled opinion and for the cure of disease, the use of these agents is subversive of the animal functions, and is a certain means of embittering and shortening life. It is doubtful whether the freedom of the subject ought to be permitted to extend to the uncontrolled self-indulgence in these poisons. The indulgence indicates an unsound reason which requires to be governed by sound reason, temperately enforced. XIII The food on which the man who would be healthy should live should be selected so as to ensure variety without excess. Animal food should not be taken oftener than twice daily. The amount of animal and vegetable food combined should not exceed thirty ounces in the twenty-four hours, and for the majority of persons an average of twenty-four ounces of mixed solid food, a third only of which should be animal, is sufficient. All animal foods should be eaten while they are fresh and after they are well cooked. The habit of eating underdone flesh is an almost certain cause of parasitic disease. The amount of fluid taken, in any form, should not exceed an average of twenty-four ounces daily. Water is the only natural beverage. XIV To escape the injuries arising from impure air it is necessary to attend to the following rules: To avoid the admission into closed apartments of air charged with any substance that offends the sense of smell. To avoid surcharging the air with vapour of water. To keep the temperature in every room as nearly as possible at the safe standard of 60° Fah. To take ample means of allowing air to escape from the room by every available outward draught, by the chimney flue especially. To admit air freely at all times, and, when a room is not in use and the external air is not charged with moisture, to allow the entrance of air from without through every window and door. XV Occupations of every kind, however varied they may be, require to be alternated, fairly, with rest and recreation. It is the worst mistake to suppose that most and best work can be done when these aids are omitted. Strictly, no occupation that calls forth special mental and physical work should fill more than one-third of the daily life. The minds of men of all classes ought now to be devoted to the promotion of a systematic method by which the productive labour of every life should be carried on within the limited term of eight hours in the twenty-four. The body of man is not constructed to run its completed circle under a heavier burden of labour. XVI