664 ACTIVE IMMUNIZATION 



profound and favorable influence upon metabolism, increasing elimina- 

 tion and tending at the same time to increase body weight.. 



It is apparent, therefore, that the administration of either an autog- 

 enous or stock bacterial vaccine may produce beneficial results not 

 only through the production of specific antibodies but also by means of 

 certain general and non-specific agencies. To secure these results suffi- 

 ciently large doses must be given. It is well known that we possess 

 general defences against infection, and it is entirely logical to assume 

 that these are operative in combating disease and may be subjected to 

 stimulation and increased activity. In my opinion we should still prefer 

 the use of autogenous vaccines, increase their immunizing powers by 

 more attention to the technic of their preparation, and adhere to our 

 belief in their probable specific effects, while realizing that their adminis- 

 tration may also stimulate non-specific agencies of therapeutic value. 

 Further investigations are required to produce safe and satisfactory 

 preparations of some protein adapted for this form of therapy if the 

 non-specific activity of some protein is alone desired. 



In this form of therapy with non-specific bacterial vaccines, typhoid 

 vaccine has been generally administered by intravenous injection. Some 

 reaction is apparently necessary for therapeutic results, but severe and 

 undesirable reactions may be produced with marked rise in temperature, 

 severe headache, and chill. If this form of therapy is employed the 

 physician should very carefully consider the possibility of these severe 

 reactions following an injection and the ability of the patient to with- 

 stand them. Small doses of typhoid vaccine, as 40,000,000 to 70,000,000 

 bacilli, should be selected for the first injection if given intravenously, 

 with a gradual increase until some fever and leukocytosis result. Subcu- 

 taneous injections with larger doses may be tried, as they are safer but 

 slower in action. The usual forms of therapy and particularly the re- 

 moval or treatment of foci of infection should receive careful attention. 

 Until this form of treatment is better understood and a purified protein 

 provided in standardized dosage, the physician should exercise extreme 

 caution, and particularly with intravenous injections. 



Living versus Dead Vaccines. Barring accidents, the employment 

 of a living virus is the most certain way of calling forth a maximum 

 output of antibodies. There is at present no satisfactory explanation 

 for this except that heat-labile substances destroyed in the ordinary 

 preparation of bacterial vaccines have antigenic properties (Smith). 

 Living vaccines are also capable of penetrating into deeper tissues, 

 whereas dead vaccines may remain where they are deposited. Similarly 

 living viruses are capable of exerting a continuous action and of de- 



