[476] CHAPTER XV 



PROTECTIVE VACCINATIONS 



Vaccinations against I. Small-pox. II. Sheep-pox. III. Rabies. IV. Rinderpest. 

 V. Authrax. VI. Symptomatic Anthrax. VII. Swine Erysipelas. VIII. Pleuro- 

 pneumonia in the Bovidae. IX. Typhoid Fever. X. Plague. XI. Tetanus. 

 XII. Diphtheria. 



IN the preceding chapters I have attempted to present to the 

 reader a general view of the phenomena of immunity against infec- 

 tive micro-organisms and against their toxic products. I shall now 

 attempt to give a review of the facts acquired in connection with 

 the prevention of the infective diseases of man and of the chief 

 domestic animals by means of vaccination. Vaccinations as we 

 know can be carried out either with viruses the constituents of 

 which have not as yet been recognised, with micro-organisms grown 

 on various nutrient media, with virulent or attenuated micro-organ- 

 isms, or with microbial products deprived of the micro-organisms by 

 which they have been built up. In addition to these methods we 

 may vaccinate with protective or antitoxic serum and other body 

 fluids, with normal serum, or with a whole series of fluids not 

 excepting water. 



I. Vaccination against small-pox. We naturally commence the 

 series with vaccination against small-pox, which is one of the oldest 

 and one of the best known, having been practised in every country 

 in Europe for more than 100 years. Small-pox, a very contagious 

 and fatal malady, was very rife in the 18th century. Large cities like 

 London and Paris were severely affected. One-tenth of the total 

 mortality was due to this disease. According to statistical informa- 

 tion, very exact for that epoch, the deaths from small-pox in London 

 [477] during the course of the second half of the century (17511800) 

 numbered more than 100,000 (102,112) persons. During the first 



