"Out of more than 10,000 children vaccinated at Brussels with animal lymph, from 1865 to 1870, and who went through the terrible epidemic of smallpox, which in 1870 and 1871 frightened the world, not a single one was to my knowledge reported as being attacked by the disease. The same immunity was shared by those, a much larger number, whom I had re-vaccinated and who at the same time were living in epidemic centers."--Dr. Warlemont, of Brussels. [INFECTIOUS DISEASES 205] Who should be Vaccinated.--Everybody, old and young, for his own interest, and that he may not become a breeding place for the distribution of smallpox to others, should seek that protection from smallpox which is afforded by vaccination alone. It is believed that all persons except those mentioned in the following paragraph may, if the operation is properly performed, at the proper time, and with pure bovine virus, be vaccinated with perfect safety to themselves. Even those who have had smallpox should be vaccinated, for otherwise they may take the disease; and it seems to be proved that a larger proportion, of those who have smallpox a second time, die than of those who have the disease after vaccination. Who should not be Vaccinated.--Unless exposure to smallpox is believed to have taken place or likely to take place, teething children, pregnant women, persons suffering from measles, scarlet fever, erysipelas, or susceptible to and recently exposed to one of these diseases, persons suffering with skin diseases or eruption, and in general feeble persons not in good health, should not be vaccinated. In all cases in which there is any doubt as to the propriety of vaccinating or postponing vaccination the judgment of a good physician should be taken. The restriction, as to vaccinating teething children makes it important that children should be vaccinated before the teething process has begun, because smallpox is very much more dangerous than vaccination. Smallpox is exceedingly dangerous to pregnant women. When should a person be Vaccinated.--The sooner the better as a rule, and especially whenever there is much liability of exposure to smallpox. Children should be vaccinated before they are four months old; those who have never been vaccinated, should, except teething children, be vaccinated at once. Because the vaccination often loses its protective power after a time, those who have been vaccinated but once or twice should, in order to test and to increase the protective power of the former vaccination, be vaccinated again, and as often as the vaccination can be made to work. In general, to insure full protection from smallpox, one should be vaccinated as often as every five years. It has been found that of those who have smallpox the proportion of deaths is very much less among those who have three or four good vaccination scars than among those who have but one scar.