PROPHYLACTIC TYPHOID INOCULATION 35 



Pfeiffer-Kolle's Experiments. 



Pfeiffer and Kolle prepare their vaccine by growing typhoid bacilli 

 on agar cultures and suspending a twenty-four hours' growth in physio- 

 logical NaCl solution. The normal platinum loop is the unit of standard- 

 ization. A full grown agar culture is considered as 10 normal loops and 

 as such it is diluted in 4.5 c.cm. of saline. This emulsion is placed in 

 a thermostat at 60 C . for two hours and then tested for its sterility. Suffi- 

 cient 5 per cent, phenol solution is next added to the suspension to bring 

 the contents up to a 0.5 per cent, carbolic solution, and the final emulsion 

 is again heated at 60 C. for thirty minutes. One c.cm. of the vaccine 

 is thus equivalent to two normal loops of culture. The amounts of 

 vaccine to be injected have not yet been definitely decided upon. The 

 best dosage so far is the following: 



For the first injection: 0.3 c.cm. of the vaccine. 

 For the second injection: 0.8 c.cm. of the vaccine. 

 For the third injection: i.o c.cm. of the vaccine. 



The injection is made subcutaneously between the breast and clavicle. 



The local and general reactions are the same as those observed with 

 Wright's method. As a result of the injection only increased agglutinins 

 and bacteriolysins have been found in the blood serum. Bacteriotropins 

 have not as yet been examined for. 



The effects of these inoculations seem to be very good. Protection is prolonged 

 according to the increase in the number of injections, and if inoculated individuals do 

 become infected, they run a very much milder course of the disease. 



The following statistics as given by Kuhn indicate the results: 



Inoculated. Non-inoculated. 



Very slightly ill 186 (50. 13 per cent.) 331 (36. 55 per cent.) 



Moderately ill 96 (25.88 per cent.) 225 (24.85 per cent.) 



Severely ill 65 (17.52 per cent.) 234 (25,80 per cent.) 



Deaths 24 ( 6.47 per cent.) 116 (12.80 per cent.) 



371 (100 per cent.) 906 (100 per cent.) 



The' prophylactic immunity according to Kuhn lasts one year. Kolle has under- 

 taken similar experiments against cholera. 



