OPSONINS TROPINS BACTERIAL VACCINES 173 



8. Dilute the suspension to the required degree with phenol, so 

 that the finished vaccine shall contain 0.25 to 0.5 per cent, of it. This 

 is the finished vaccine. 



9. Redetermine sterility if necessary. 



Sensitized Vaccines. Killed bacteria which have been immersed 

 in a specific serum sensitized vaccines are said to be less liable 

 to produce general and local reactions. The immunity developed 

 in response to the injection of these sensitized vaccines is said to 

 appear more rapidly, and doses thirtyfold those of unsensitized vac- 

 cines may be injected without serious effect. 



The Injection. The skin at the site of injection is cleaned with 

 soap and water and then with alcohol; or better, after carefully dry- 

 ing it is painted with tincture of iodin. The required amount of 

 vaccine is injected subcutaneously through this area, from a sterile 

 syringe. 



The Dosage and Frequency of Injection. It is advisable to begin 

 with small doses of vaccine, quantities which past experience has 

 shown to do no harm so far as can be determined by clinical evidence, 

 and to increase the size of the dose gradually, the injections usually 

 being given at intervals of about a week. If no change results from 

 the treatment, larger doses may be tried. If the symptoms become 

 aggravated the doses should be diminished and given at less frequent 

 intervals. Generally speaking, in the more acute cases smaller doses 

 should be selected to begin with, larger doses being reserved for the 

 more chronic cases. The amounts of vaccine to be injected vary widely 

 according to different investigators. Generally speaking, the following 

 figures are fairly representative : 



Minimum. 1 Maximum. 1 Average. 1 



Staphylococcus ...... 5.0 1000 25 



Streptococcus 2.5 100 25 



Pneumococcus 2.5 100 25 



Goriococcus 2.5 300 30 



Coli 5.0 1000 100 



Pyocyaneus ........ 5.0 1000 100 



Indications for the Use of Bacterial Vaccine. Generally speaking, 

 bacterial vaccines are contraindicated in acute disease, but may be 

 employed in practically any localized infection, or an infection which 

 has become chronic. 2 



1 Figures represent millions of organisms. 



2 An excellent discussion of the present status of vaccine therapy is that of Theobald 

 Smith, An Attempt to Interpret the Present-day Use of Vaccines, Jour. Am. Med. Assn., 

 1913, Ix, 1591. 



