OPSONINS— TROPINS—BACTERIAL VACCINES 193 
It should be borne in mind that vaccine therapy cannot be reason- 
ably applied unless an exact bacteriological diagnosis has been made. 
The immunizing effects of vaccines are definitely limited by the 
ability of the normal tissues of the patient to produce antibodies; 
to inject too frequently or in too large doses may not only be barren 
of results— it may result in a decrease rather than an increase of 
resistance to infection. 
It is essential for the best results of vaccination that the focus of 
infection be so situated anatomically that the newly formed anti- 
bodies be drawn to the infected area by the production of local hyper- 
emia. Infections of long standing naturally respond to treatment 
more slowly than newly acquired infections. 
Results. — Following the brilliant discovery of -Tenner that vaccine 
virus will afford protection against smallpox, it is quite natural that 
attention should be directed toward bacterial vaccines as possible 
preventive and remedial agents. Bacterial vaccines have been tried 
in a considerable number of infections, principally of the contagious 
types of disease. Quite early in the history of these trials, Hektofen^ 
pointed out that non-specific vaccines not infrequently induce reac- 
tions quite similar to those evoked by vaccines composed of homologous 
organisms, namely, a chill and, fever followed by return to normal, fre- 
quently by sweating and improvement of the general condition of the 
patient. Since that time much attention has been devoted to the 
phenomena of this non-specific protein therapy.- Such observations 
would seem at first sight to weaken or discredit the prophylactic and 
therapeutic use of homologous vaccines, but this has not been the case. 
Opinions, however, differ widely as to the value of vaccines. 
According to the theory underlying bacterial vaccination, subacute 
and chronic inflammatory processes which are localized should give the 
best therapeutic results, and such in general appears to be the case. 
For example, a Streptococcus septicemia abates, and leaves a joint 
involvement, or a heart valve vegetation. Vaccine therapy has 
apparently a better chance of producing favorable results during 
this secondary stage than during the earlier acute septicemic stages. 
Generally speaking, gonorrheal arthritis, pneumonias which resolve 
by lysis, pus sinuses and localized colon infections are susceptible to 
vaccine treatment. Staphylococcus vaccines have given the most 
consistent and satisfactory therapeutic results. Furuncles, severe 
carbuncles, some cases of acne, and even low-grade Staphylococcus 
septicemias frequently yield rather readily to vaccine therapy, especi- 
ally with homologous vaccines. Streptococcic and pneumococcic 
infections are much more resistant, generally speaking, to vaccine 
treatment than are staphylococcus infections. The results have been 
either negative or uncertain in acute inflammations of the mucous 
membranes of the intestines, bladder, throat, etc. 
1 Jour. Am. Med. Assn., 1916, 66, 1591. 
2 See Petersen: Protein Therapy and Non-specific Resistance, 1922, for discussion. 
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