494 BIOLOGY OF PNEUMOCOCCUS 



formation may be followed to their logical end, and also for the 

 information of readers who may not have access to original source 

 material, the results attending the use of vaccines for the preven- 

 tion and cure of pneumococcal disease will be dealt with in sum- 

 marized form. 



PROPHYLAXIS 



Because of the enormous toll exacted by pneumonia among the 

 ranks of native workers in the diamond mines in South Africa, 

 Maynard (1913) 872 sought whatever benefit might accrue to the 

 men by the injection of vaccines prepared from Pneumococcus. In 

 the beginning of the investigation, two doses of 40 to 60 million, 

 then of 100 to 200 million, and finally of 300 million organisms 

 given immediately upon the arrival of the natives on the Rand ap- 

 peared to reduce the incidence of pneumonia for a period lasting 

 not over four months. There was no evidence that the preventive 

 treatment influenced case fatality, except possibly for a very short 

 time after injection. On account of historical interest and because 

 of the contributions of the senior author to the subject of bac- 

 terial vaccines, the work of Wright, Morgan, Colebrook, and 

 Dodgson (1914) 1545 " 6 should be cited. Administering heat-killed 

 broth cultures in subcutaneous doses representing 300 million to 

 600 million pneumococci to several thousand native Africans in the 

 Rand mine, the authors reported an apparent decrease of approxi- 

 mately 50 to 60 per cent in the incidence of pneumonia among the 

 vaccinated men when compared to the attack-rate among un- 

 treated controls. 



During the mobilization of American troops at Camp Upton 

 during the World War, Cecil and Austin 204 vaccinated more than 

 twelve thousand men, giving three or four injections at intervals of 

 five to seven days of suspensions of heat-killed cultures of Type I, 

 II, and III pneumococci. The total dosage consisted of six to nine 

 billion organisms of Types I and II and four and one-half to six 

 billion of Type III pneumococci. In the ten weeks which elapsed 



