92 Immunity 



or an entirely different disease. Cow-pox was, however, common 

 in the days when smallpox was frequent, and has now become 

 extremely rare. 



(b) Experimental Infection. I. Inoculation: This is an attempt 

 to prevent the occurrence of a fatal attack of an infectious disease, 

 by inducing a mild attack of the same disease when the individual 

 is in good health, and at his maximum resisting power. The oldest 

 experiments date from unknown antiquity and were practised 

 in China and other Oriental countries for the purpose of preventing 

 smallpox. The Chinese method of experimentally producing 

 variolous infection was very crude and consisted in introducing crusts 

 from cases of variola into the nose, and tying them upon the skin. 

 The Turkish method was much more neat, in that a small quantity 

 of the variolous pus was introduced into a scarification upon the skin 

 of the individual to be protected. The following extract is from a 

 letter of Lady Montague,* wife of the British Ambassador to 

 Turkey, who brought the so-called " inoculation " method from 

 Turkey in the early part of the eighteenth century (1718): 



" . . . . . Apropos of distempers, I am going to tell you a thing that I am 

 sure will make you wish yourself here. The smallpox, so fatal, and so general 

 amongst us, is here entirely harmless by the invention of ingrafting, which is 

 the term they give it. There is a set of old women who make it their business 

 to perform the operation every autumn, in the month of September, when the 

 great heat is abated. People send to one another to know if any of their family 

 has a mind to have the smallpox; they make parties for this purpose, and when 

 they are met (commonly fifteen or sixteen together) , the old woman comes with 

 a nut-shell full of the matter of the best sort of smallpox, and asks what vein 

 you please to have opened. She immediately rips open that you offer to her 

 with a large needle (which gives you no more pain than a common scratch), and 

 puts into the vein as much venom as can lie upon the head of her needle, and 

 after binds up the little wound with a hollow bit of shell; and in this manner 

 opens four or five veins. The Grecians have commonly the superstition of 

 opening one in the middle of the forehead, in each arm, and on the breast, to 

 mark the sign of the cross; but this has a very ill effect, all these wounds leaving 

 little scars, and is not done by those that are not superstitious, who choose to have 

 them in the legs, or that part of the arm that is concealed. The children of young 

 patients play together all the rest of the day, and are in perfect health to the 

 eighth. Then the fever begins to seize them, and they keep their beds two days, 

 very seldom three. They have very rarely above twenty or thirty [pocks] in 

 their faces, which never mark; and in eight days' time they are as well as before 

 their illness. Where they are wounded, there remain running sores during the 

 distemper, which I don't doubt is a great relief to it. Every year thousands 

 undergo this operation; and the French embassador says pleasantly, that they 

 take the smallpox here by way of diversion, as they take the waters in other 

 countries. There is no example of any one that has died in it; and you may 

 believe I am very well satisfied of the safety of this experiment, since I intend to 

 try it on my dear little son. 



"I am patriot enough to take pains enough to bring this useful invention into 

 fashion in England; and I should not fail to write to some of our doctors very 

 particularly about it, if I knew any one of them that I thought had virtue enough 

 to destroy such a considerable branch of their revenue for the good of mankind. 

 But that distemper is too beneficial to them not to expose to all their resentment 

 the hardy wight that should undertake to put an end to it." 



* See the "Letters of Lady Mary Wortley Montague;" letter to Miss Sarah 

 Chisives dated Adrianople, April i (O. S.), 1717. 



