THE ADMINISTRATION OF A BACTERIAL VACCINE 219 



In more acute infections, and in delicate persons, smaller doses are 

 usually indicated. It is well to make the first dose small, and if no reac- 

 tion occurs within forty-eight hours, a second and a larger dose may be 

 given. If, however, the patient presents other symptoms of a general 

 reaction, the dose given was large enough, and may be repeated, as 

 necessary, at intervals of from five to seven days. It should be care- 

 fully borne in mind that an increase in dosage is contraindicated so long 

 as any sign of general or focal reaction is produced and steady progress 

 is maintained. One should always be on guard to detect any signs of 

 fresh infection by some other organism, and if a given vaccine is failing 

 to exert a beneficial effect, additional cultures should be made, instead 

 of continuing to administer dose after dose of the same vaccine. 



The intervals at which injections are to be made are of some im- 

 portance. It is certainly better to wait too long than to inoculate 

 prematurely, but the ghost of the " negative phase" is always too prom- 

 inent in the minds of the inexperienced. The inoculations may be 

 given while improvement is still in progress or convalescence well es- 

 tablished, in the endeavor to secure a summation of positive phases of 

 clinical improvement; or one may wait for the first signs of retrogression 

 before administering another dose. The former method is the preferable 

 procedure, but is difficult to accomplish; the latter is less ideal, but 

 is easier to perform and more devoid of risk. 



The dosage varies according to whether the infection is acute or 

 chronic, the nature of the microorganism, and the age of the patient. 

 No fixed rules can be given. In acute infections the dose should be 

 small and may frequently be repeated; in chronic infections larger doses 

 may be given at longer intervals. If in doubt as to the size of the dose 

 to be given, it is better to give a small dose, and carefully observe the 

 effect on the patient, letting this serve as an index to subsequent doses. 

 Children tolerate relatively large doses of bacterial vaccines, but the 

 dosage should depend on the weight and not on the age of the child. 



The following is a list of the ordinary doses for adults of various bac- 

 terins : 



Staphylococcus aureus . . ... 100,000,000 to 1,000,000,000 



Staphylococcus albus and citreus 200,000,000 to 1,000,000,000 



Streptococcus pyogenes 25,000,000 to 200,000,000 



Gonococcus 25,000,000 to 200,000,000 



Typhoid bacillus 250,000,000 to 1,000,000,000 



Colon bacillus 100,000,000 to 1,000,000,000 



