When he is two months old, as the sooner he is protected the better. Moreover, the older he is the greater will be the difficulty in making him submit to the operation, and in preventing his arm from being rubbed, thus endangering the breaking of the vesicles, and thereby interfering with its effects. If small-pox be prevalent in the neighborhood, he may, with perfect safety, be vaccinated at the month’s end; indeed, if the small-pox be near at hand, he _must_ be vaccinated, regardless of his age and regardless of everything else, for small-pox spares neither the young nor the old, and if a new-born babe should unfortunately catch the disease, he will most likely die, as at his tender age he would not have strength to battle with such a formidable enemy. “A case in the General Lying-in-Hospital, Lambeth, of small-pox occurred in a woman a few days after her admission and the birth of her child. Her own child was vaccinated when only four days old, and all the other infants in the house, varying from one day to a fortnight and more. All took the vaccination; and the woman’s own child, which suckled her and slept with her; and all escaped the small-pox.” Communicated by Sir Charles Locock to the author. 51. _Do you consider that the taking of matter from a child’s arm weakens the effect of vaccination on the system?_ Certainly not, provided it has taken effect in more than one place. The arm is frequently much inflamed, and vaccinating other children from it abates the inflammation, and thus affords relief. _It is always well to leave one vesicle undisturbed?_ 52. _If the infant has any “breaking-out” upon the skin, ought that to be a reason for deferring the vaccination?_ It should, as two skin diseases cannot well go on together; hence the cow-pox might not take, or, if it did, might not have its proper effect in preventing small-pox. “It is essential that the vaccine bud or germ have a congenial soil, uncontaminated by another poison, which, like a weed, might choke its healthy growth.” The moment the skin be free from the breaking-out, he must be vaccinated. A trifling skin affection, like red gum, unless it be severe, ought not, at the proper age, to prevent vaccination. If small-pox be rife in the neighborhood, the child _must_ be vaccinated, regardless of _any_ “breaking-out” on the skin. 53. _Does vaccination make a child poorly?_