mense quantities of oxygen and develop immense activity. Each animal has, as Prof. Foster believes (page 812), its own peculiar quantity, its coefficient, so to speak, of oxygen, which it consumes—an amount which, judging from the few instances he gives, seems to vary with intelligence; thus the dog consumes more than the rabbit per pound of its weight, and a man more than a dog. In the same way, a waking man consumes more oxygen than a sleeping man, a man at work than a sedentary man, a young man than an old man, a young child more than the young man. The restless activity of children marks both their great consumption of oxygen and their pressing need for it by being allowed to breathe abundance of pure air. Rapid and extensive waste is going on in every child's body. Tissue of every kind, including bone, is being constantly broken down in order that it may be built up anew on a larger scale, and it is therefore the greatest cruelty in their case not to provide them in fullest measure with the purest air. Unhappily, very little thought is given to this matter; and with quite young children whose need is the greatest of all our nurseries are only too often mere slaughter-houses. Mothers of all classes should try to see the meaning of the fact that out of four deaths of infants one takes place from lung collapse, a state that often follows bronchial inflammation (see R. D. Powell, Lungs; Quain, page 861), and probably of ten indicates the source of the mischief. Dr. Douglas Powell significantly says, "All causes that interfere with respiratory efficiency favor the occurrence of the condition named."
It is now right for us to look at the subject of these waste poisons in special reference to the skin. Without referring here to the different calculations made on this subject, it is enough to say that much less carbonic acid escapes from the skin than from the lungs; more water (if we are to follow Prof. Foster who differs from other authorities, who again differ among themselves we may say roughly, 1·5 pound from lungs, and 2·5 pounds from the skin per day), and a larger amount of solid matter The solid matter is put at one or two per cent of the whole 2·5 pounds and two thirds of this one or two per cent is organic matter containing the poisons in question. We can see the importance of the skin, as an organ of excretion, in various ways. In the first place, the provision of an enormous number of sweat-glands un-
- So it has been stated. It is also interesting to quote the statement from the Registrar-General's Report for 1889, that there were in that year 71,056 deaths of male infants (not over twelve months) in England, and out of this number, 13,805 (roughly speaking, about one in five) died of diseases connected with the respiratory system. It is right to add that lung collapse may follow many different kinds of illness.
- Thus we should have from 118·3 to 236·6 grains of organic matter excreted by the skin in twenty-four hours.