OPSONINS TROPINS BACTERIAL VACCINES 171 



Wright, 1 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 anti- 

 bodies 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 infection, 

 and will reinforce the partially depleted defensive forces which have 

 ineffectually opposed the invading organisms. 



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 antibodies 

 be drawn to the infected area by the production of local hyperemia. 

 Infections of long standing naturally respond to treatment more 

 slowly than newly acquired infections. 



Preparation of Vaccines. Much discussion has arisen concerning 

 the use of autogenous vaccines as compared with stock or polyvalent 

 vaccines. So little is actually known of what vaccines may accomplish 

 in the body that it is impossible to answer this question definitely. 

 It is desirable, however, to retain in the vaccine all possible anti- 

 genie properties which were possessed by the organism in the body. 

 It is a well-known fact that certain kinds of organisms rapidly lose 

 their ability to produce disease when they are grown for any length 

 of time outside the body. Others retain their virulence for some 

 time. This would appear to indicate that stock vaccines of the former 

 would be unsatisfactory, while stock vaccines of the latter might be 



1 Proc. Roy. Soc. of Med., London, 1910, iii. 



