192 ANTIGENS AND THE TECHNIC OF SERUM REACTIONS 
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.' Maximum. i Average.' 
Staphylococcus 5.0 1000 25 
Streptococcus 2.5 100 25 
Pneumococcus 2.5 100 25 
Gonococcus 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- 
Therapeutic Vaccination.— In chronic, long-dra\\ii out focal or local 
infections, the invading microbes are either holding their own or 
gaining the ascendency, and the object of bacterial vaccination is to 
turn the tables on the invaders. The products of immunization must 
be used at once, and the organisms comprising the vaccines for this 
purpose cannot ordinarily be as resistant as their originals in the host. 
The underlying principle of therapeutic vaccination, according to 
Wright,^ is to exploit the normal tissues of the body in the interest 
of the infected tissue. For this purpose, microbes similar to those 
causing the infection (autogenous organisms) are inoculated into 
some other part of the body. This inoculation is not, to use Wright's 
phraseology, a mere replica of the original infection; there are two 
important points of difference: (1) The microbes of the vaccine are 
killed, so that their multiplication within the host is impossible; 
(2) the dose of vaccine must be so regulated that the tissues of the 
host at the site of inoculation and elsewhere must inevitably win. 
Victory of the host is brought about through the elaboration of specific 
antibodies generated in the healthy tissues on a scale more than 
adequate to bring about a destruction of the organisms introduced 
into the healthy tissue. The surplus of the specific antibodies will 
find its way, through blood and lymph channels, to the focus of infec- 
tion, and will reinforce the partially depleted defensive forces which 
have ineffectually opposed the invading organisms. 
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, 60, 1591. 
3 Lancet, 1910, ii, 863. 
