480 PATHOGENIC MICROORGANISMS 



mouth of influenza patients, brushing of the teeth and cleansing of the 

 mouth with sodium bicarbonate solution, or salt solution gargle to 

 which 20 per cent or 30 per cent alcohol can be added. The patient 

 should be carefully guarded from infection by the doctors and nurses 

 who should wear gauze masks for this purpose. This is not primarily 

 in our minds a precaution to protect the physicians and nurses, but 

 rather the other way around. Dangers of transmission of pneumo- 

 mococci and streptococci from bed to bed should be guarded against 

 as above in the case of measles. The pneumonias which occur during 

 an influenza epidemic are very rarely due to influenza bacillus infec- 

 tion of the lung alone. The fatal disease is caused by a large variety of 

 organisms, including the various pneumococci, the streptococci and 

 some others. In any one particular place the majority of cases may be 

 due to one or another of these organisms, this depending somewhat 

 upon the bacteria which happen to be most prevalent in this com- 

 munity, and are passed from mouth to mouth under conditions of 

 generalized respiratory transmission, occurring in this place. Thus, 

 MacCallum and Cole studied a secondary pneumonia epidemic in 

 which hemolytic streptococci were responsible for most of the cases, 

 but usually the pneumonias following in the train of influenza are not 

 of a single type, but caused by any virulent member of the lung 

 invading group of bacteria that happened by chance to lodge on the 

 mucous membranes of the subject rendered susceptible by his primary 

 disease. 



Thus, after an influenza epidemic has started, sanitary measures 

 aimed at the prevention of the fatal secondary infections must focus 

 upon the transmission factor entirely. 



Prophylactic Vaccination against Pneumococcus Infection. The 

 value of prophylactic vaccination against pneumonia is not yet def- 

 inite. Wright 92 was the pioneer in this work in 1911, but since he did 

 not know about type differentiation, the value of his work is limited. 

 The first hopeful experiments were made by Lister 93 in South Africa, 

 who typed his pneumococci by the usual agglutination method, having 

 his own types A, B, and C (B and C corresponding respectively to II 

 and I of our classification), made salt solution suspensions of the organ- 

 isms, injecting at first six to seven billion, intravenously. Later he 

 resorted to subcutaneous inoculations, giving three doses of two billion 



92 Wright and Morgan, Lancet, 1, 1914, 1 and 87. 



93 Lister, Pub. South African Inst. f. Med. Ees., 1916, No. 8. 



