the younger a child is, the more readily it parts with its heat, because the smaller it is, the larger is its surface relatively to its bulk, for the area of a body varies as the square of its dimensions, while its mass varies as their cube, and the surface of a human body is an evaporating—consequently a cooling one. The following example will make this point clearer. A cube one inch in the side has six square inches of surface to one cubic inch of bulk, while a cube ten inches in the side has 600 square inches of surface to 1000 cubic inches of bulk, so that the surface of the small cube is ten times greater in proportion to its contents than that of the large one. Now, supposing a child to be one-tenth of the size of its mother, besides its feebler powers of generating heat, it will have just ten times as much surface in proportion to its size by which to lose heat as that mother has.
The lungs in young infants are especially active, and are thus rendered more liable to become diseased than any other organ when increased work is thrown upon them by exposure to cold, and every year thousands of children fall victims to lung diseases, which are very much more common during childhood than at any other time of life, as you will see clearly from the fact that out of 379 fatal cases of pneumonia—that is, inflammation of the lungs—in London and some country districts, 228, or nearly two-thirds, were children under three years of age. But in order to give a fuller idea of the mischief done, let me quote the Registrar-General's statistics. From these we see that in one
