My firm belief, then, is, that if _every_ person were, _every seven years_, duly and properly vaccinated, small-pox might be utterly exterminated; but as long as there are such lax notions on the subject, and such gross negligence, the disease will always be rampant, for the poison of small-pox never slumbers nor sleeps, but requires the utmost diligence to eradicate it. The great Dr Jenner, the discoverer of cow-pox as a preventative of small-pox, strongly advocated the absolute necessity of _every_ person being re-vaccinated once every seven years, or even, oftener, if there was an epidemic of small-pox in the neighbourhood. 48. _Are you not likely to catch not only the cow-pox, but any other disease that the child has from whom the matter is taken_? The same objection holds good in cutting for small pox (inoculation)--only in a ten-fold degree--small-pox being such a disgusting complaint. Inoculated small-pox frequently produced and left behind inveterate "breakings-out," scars, cicatrices, and indentations of the skin, sore eyes, blindness, loss of eyelashes, scrofula, deafness--indeed, a long catalogue of loathsome diseases. A medical man, of course, will be careful to take the cow-pox matter from a healthy child. 49. _Would it not be well to take the matter direct from the cow_? If a doctor be careful--which, of course, he will be--to take the matter from a healthy child, and from a well-formed vesicle, I consider it better than taking it _direct_ from the cow, for the following reasons:--The cow-pox lymph, taken direct from the cow, produces much more violent symptoms than after it has passed through several persons; indeed, in some cases, it has produced effects as severe as cutting for the small-pox, besides, it has caused, in many cases, violent inflammation and even sloughing of the arm. There are also several kinds of _spurious_ cow-pox to which the cow is subject, and which would be likely to be mistaken for the _real_ lymph. Again, if even the _genuine_ matter were not taken from the cow _exactly_ at the proper time, it would he deprived of its protecting power. 50. _At what age do you recommend an infant to be first vaccinated_?