INOCULATION OF BACTERIAL VACCINES. 423 



Failure to recognize these different methods by which the body combats 

 bacterial invasion has been the cause of many bitter disappointments in 

 the field of serum therapy. 



So far it has been impossible to demonstrate any increase of opsonin 

 for the diphtheria bacillus by inoculation with the dead bacteria. Practi- 

 cally, however, it would seem that some antibacterial element must be 

 developed, or increased, for it is hard to understand why the local 

 condition ceases so promptly and why the diphtheria bacillus regularly, 

 though slowly, disappears from the throat if the reaction is purely anti- 

 toxic. On the other hand, it seems probable that some antitoxin is 

 produced against the bacteria that are mainly attacked by opsonins. 

 This would account for some of the partial successes achieved in the 

 antitoxic treatment of bacterial diseases that are now known to belong 

 in the opsonic army. 



Again to quote Wright's words, "it is only when bacteria or their 

 products enter the blood and endanger life that nature addresses herself 

 seriously to the task of immunization. As long as a bacterial invasion 

 is purely local, nature opposes to it no more than a passive resistance." 

 This is an important generalization and we at once see that it is the key 

 to the situation in lupus, acne, furuneulosis, gonorrheal arthritis, 

 epididymitis, urethritis, conjunctivitis, and a number of other infections. 

 Further, the production of antibacterial and antitoxic substances follow- 

 ing inoculation is a local process at the site of the inoculation. 



With these few remarks on the physiology of immunization, we can 

 proceed to a discussion of the specific application of vaccines in the 

 treatment of bacterial diseases. In order that we may successfully 

 combat bacterial invasion by use of its opsonins which are normally 

 present in the blood, two things are necessary: (1) the opsonins must 

 attack the bacteria and so alter them that they can be ingested by the 

 leucocytes; (2) the leucocytes must ingest and disintegrate the bacteria. 

 This at once gives us the key to the opsonic index which, in the case of 

 bacterial disease, is an index to what nature is doing toward immunization 

 against the specific bacterium. "Taking the opsonic index" is a fairly 

 technical procedure and has been the main stumbling block in the 

 practical use of opsonotherapy. It was not my intention to describe the 

 means of taking the opsonic index, but there seems to be so much mis- 

 understanding about it that I will give the method used in practical work. 



Ordinarily the bacteria are grown on agar. The gonococcus does not grow 

 on this medium, so I have cultivated it by taking a drop of blood from a man's 

 ear in the usual way, smearing the blood over the surface of a plain agar or 

 a gtycerine-agar tube and making my culture on it. I have made hundreds of 

 cultures in this way during the past twenty months and have very rarely had 

 a contamination. It is also very easy to obtain a pure culture of the gonococcus 

 in this way from an early case of urethritis. I have been able to induce some 

 strains of the gonococcus to grow on glyeerine-agar after a long time. 



Equal volumes of the patient's blood (from say a case of gonorrhoeal arthritis), 



