32 ACTIVE IMMUNIZATION. 



counting the number of bacteria under the microscope. At the first inocu- 

 lation, the patient received 750 to 1000 million of these dead bacteria and at 

 the second, eleven days later double the first dose injected. 



Local and general reactions follow the inoculations. Thus local redness 

 and swelling of the skin, lymphangitis and enlargement of the neighboring 

 glands are the usual consequences. The inflammation can at times be 

 severe enough to simulate erysipelas. The general symptoms, on the other 

 hand, may consist of a general feeling of illness, headache, a little fever, and 

 occasionally nausea, not infrequently accompanied by vomiting. These 

 signs of indisposition, however, pass off rapidly without leaving any perma- 

 nent ill effects. Six to eleven days after the injection, an increase in the 

 number of agglutinating, bacteriolytic and bacteriotropic bodies can be 

 demonstrated in the blood of the inoculated individual. 



As to the effects of these inoculations opinion is somewhat divided. 

 According to Wright's statistics infections have been diminished by about 

 one-half, and in single series to one-sixth or even one-twenty-eighth of the 

 former, or control number. The mortality too is much lower. Out of 

 1758 individuals who had been vaccinated, only 142 or 8 per cent, died; 

 out of 10,980 who had not been, 1800 or 16.6 per cent, met death. From 

 numbers such as these, Wright has come to the opinions he holds, and he 

 moreover believes that the period of time during which prophylactic immu- 

 nity can be maintained is from two to three years. 



Pfeiffer-Kolle's Experiments. 



Pfeifler and Kolle prepare their vaccine by growing typhoid bacilli on 

 agar cultures and suspending a twenty-four hours growth in physiological 

 NaCl solution. The normal platinum loop is the unit of standardization. 

 A full grown agar culture is considered as 10 normal loops and as such it is 

 diluted in 4.5 c.c. of saline. This emulsion is placed into a thermostat 

 at 60 for two hours and then tested for its sterility. Sufficient 5 per cent, 

 phenol solution is next added to the suspension to make up the contents 

 to a 0.5 per cent, carbolic solution, and the final emulsion is again heated at 

 60 C. for thirty minutes. One c.c. 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 ist injection: 0.3 c.c. of the vaccine. 

 For the 20! injection: 0.8 c.c. of the vaccine. 

 For the 3d injection: i .o c.c. 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 



