46 MEDICINE 



peating the well-known methods pursued by Pasteur and his pupils 

 in the use of the graduated doses of attenuated toxin contained 

 in the nerve tissues in the prophylactic treatment of rabies. To 

 Pasteur, therefore, we owe the scientific recognition of the principle 

 of protective inoculation. 



It is now a well-known fact, however, that inoculation against 

 disease was practiced by the Chinese a thousand years ago. They 

 inoculated the healthy with small-pox as a protection against the 

 disease. Variolization was also practiced in Europe in the seventeenth 

 and eighteenth centuries. We read that in 1718, Lady Montague 

 caused a son to be inoculated with variola in Italy, and that two 

 years later her daughter was inoculated in England. The practice 

 was followed in Ireland long after the successful establishment 

 of vaccine as a protection against variola. Inoculation against 

 syphilis, or syphilization, was practiced in Europe during the nine- 

 teenth century. 



We owe to Jenner, however, the first example of the protective 

 inoculation by means of an attenuated virus. This attenuation we 

 now know was established by the accidental inoculation of milch 

 cows with small-pox, producing a modified disease, vaccinia. That 

 vaccinia, produced in man by inoculation, would protect against 

 small-pox was proved when, in 1798, Jenner successfully vaccinated 

 direct from the cow, the five-year-old lad William Summers. 



The thousands of successful vaccinations which have since been 

 performed and the thousands of lives which have been saved by 

 vaccination are proof of its validity and utility. The immunity 

 established by protective inoculation is apparently the same as 

 that induced by an unmodified attack of variola. 



Serum Therapy 



When chemistry had revealed the nature of bacterial poisons and 

 experiments established their relation to the phenomena of disease, 

 it was proved that substances were formed in artificial culture media 

 and in the blood and tissues of infected animals which had the power 

 to neutralize the effect of the bacterial poison in other animals 

 infected with the same organism. Further investigation showed 

 that an animal inoculated with the laboratory preparation of anti- 

 toxin was protected against the disease. 



Furthermore, it was found that the blood serum of an animal 

 inoculated with bacteria in a non-fatal and repeated dose contained 

 an antitoxin. When the blood serum of an infected animal was 

 injected into a healthy animal, the latter was protected against the 

 original disease. 



Antitoxin was, therefore, proved to be formed in artificial media 



