VACCINATION 415 



system they are fixed to the receptors by their haptophorons 

 elements, and their toxophorovis elements are therefore free, and if 

 in sufficient numbers or amount produce the toxic changes. If the 

 dose of toxin molecules is small, the mother cell is able to throw off 

 the receptor plus the toxin (E + T), which thereby becomes free in 

 the blood. The central atom group, however, is able to produce new 

 receptors, which in their turn come to be free in the blood. As a 

 result of repeated loss, the regeneration of receptors becomes an over- 

 regeneration, and the excess of unfixed receptors become free in the 

 blood, constituting antitoxin molecules. When forming part of the 

 mother cell the receptors anchor the toxin which is thus able to set 

 up toxic effects in the body cells and tissues, but when the receptors 

 are free in the blood (E + T), we have an inert compound, and 

 therefore no toxic effect. This ingenious theory of Ehrlich explains 

 the facts of antitoxic effect better than any other, and though not 

 established, and still requiring much more elucidation, is the theory 

 which mostly holds the field at the present time. 



The Application of the Ppinciples of Immunity 



We propose now to consider in some detail four illustrations of 

 the application of the facts concerning immunity to the prevention 

 or treatment of disease, viz., vaccination, Pasteur's treatment of 

 rabies, antityphoid and antiplague inoculation, and antitoxin inocu- 

 lation for diphtheria. The vaccination in small-pox is an inoculation 

 of the viriis of an attenuated form of the disease; the rabies inocula- 

 tion is a transmission of the vital products of the attenuated disease ; 

 the typhoid and plague inoculations are of pure cultures of living 

 virus from outside the body ; and the diphtheria inoculation is the 

 introduction of antitoxins (passive immunity).* 



Vaccination for Small-pox 



In 1717, Lady Mary Wortley Montaguf described the inoculation 

 of small-pox as she had seen it practised in Constantinople. So 

 greatly was she impressed with the efficacy of this process, that she 

 had her own son inoculated there, and in 1721, Mr Maitland, a 

 surgeon, inoculated her daughter in London. This was the first time 

 inoculation was openly practised in England, j For one hundred and 

 twenty years small-pox inoculation (or variolation, as it is more 



* See also Serums, Vaccines, and Toocines, W. C. Bosanquet, 1904. 



t The friend of Addison and Pope, who married Mr Edward Wortley Montagu 

 in 1712, and on his appointment to the ambassadorship of the Porte in 1716 went 

 with him to Constantinople. They remained abroad for two years, during which 

 time Lady Wortley Montagu wrote her well-known Letters to her sister the Countess 

 of Mar, Pope, and others. 



J Crookshank, History and Pathology of Vaccination. 



