AnnualReport-1909 — Page 236

K 34-

# Memorandum on the subject of Vaccination and Re-vaccination for the information of School Masters and Others.

One of the diseases which has caused the greatest number of deaths in Europe in past years, and which still causes many deaths and much disfigurement in China, is Small-pox.

It is very seldom indeed that a person suffers from a second attack of Small-pox and there are some seasons during which outbreaks of very severe and fatal Small-pox occur, and other seasons in which the disease is not so virulent. This no doubt suggested the idea that if healthy persons were deliberately given an attack of the disease during a mild season they would have a very good chance of recovery and would thus be protected from contracting the disease again should a virulent outbreak occur at some later date. This method of what is called "PROTECTIVE INOCULATION" was practised in India several hundreds of years ago and was introduced from India into Europe and became quite common in England from the year 1700.

The same method of protection found its way into China, and even at the present day this method is largely practised throughout this country, the usual procedure being to place some of the Small-pox crusts, perfumed with a little musk and wrapped in wool, into the nostrils of the person. This is followed, some days later, by the usual Small-pox rash over the face and body, with fever and general sickness, and if the person is fortunate he recovers and has thus acquired, in most cases, protection against future outbreaks of Small-pox, but at the cost of at least two or three weeks of serious illness, and at the risk of his life, for many of these inoculation cases die.

Fortunately, however, the discovery was made in Europe at the end of the eighteenth century that cows and calves suffer from a disease very similar to Small-pox, and that if we take the inoculation crusts from this animal, instead of from a human case of Small-pox, we can protect persons from Small-pox without producing any serious illness or running any risk of loss of life. This process is called "Vaccination" and its introduction is associated with the name of Jenner who first tried it in England in 1796. It is now in general use throughout almost the whole world, and there is usually a law that infants shall be vaccinated before they are six months old and that inoculation with human Small-pox material is illegal and will be severely punished.

The result of this general vaccination of infants has been to enormously reduce the number of deaths from Small-pox and to alter very materially the age-incidence of the disease. In the 18th century almost all the cases of Small-pox occurred in infants and very young children, as many as 90 per cent. of the total deaths from this disease were among them.