424 WHITilORE. 



drawn directly from the ear; a 1 per cent sodium citrate solution in normal 

 salt ; and a normal salt emulsion of a young culture of gonococcus, are mixed 

 in a pipette and put in the incubator at 38° for twenty minutes. At the end 

 of this time the mixture is blown out on slides, stained, and the number of 

 cocci ingested by, say, 100 leucocytes are counted and averaged. Suppose the 

 average is two. Exactly the same procedure is gone through using a normal 

 man's blood instead of the patient's. Perhaps here the average is four. This 

 normal man's opsonic index is taken as 1. So, since the average number of 

 cocci taken up by the patient's leucocytes is one-half the average number taken 

 up by the normal man's blood, it follows that the patient's opsonic index is 0.5. 



We see that the opsonic index is purely a matter of relative amounts 

 of opsonins in two samples of blood, one of which is normal. The 

 temperature at which the reaction is carried on niay vary from 37° to 

 39° and the time from fifteen to thirty minutes, but both bloods must 

 be treated exactly alike as to temperature and time. 



I will not enter into a discussion of Simon's method of determining 

 the percentage of phagocytic leucocytes, or the relative merits of the two 

 methods. One of my main objects, as I said above, is to impress the fact 

 that the taking of the opsonic index has nothing to do with the actual 

 treatment of the case; that in certain bacterial diseases, enough has 

 been done to place opsonotherapy beyond the experimental stage; and 

 that the dosage has been determined accurately enough so that the 

 vaccine can be inoculated and the results of treatment determined by the 

 progress of the ease. Thus, while the determination of the opsonic index 

 is the only scientifically accurate method of following the effect of the 

 inoculation, practically, in some diseases the progress of the case is a 

 sufficient guide as to the effects of the treatment. Again, since it has 

 been shown that killed cultures of bacteria retain their opsonin producing 

 properties for weeks, the actual manufacture of the vaccine is not a 

 necessary part of the treatment of a particular ease. 



Wright used Koch's new tuberculin in the treatment of local tuber- 

 culosis. Burroughs, Wellcome and Company have placed on the market 

 vaccines for use against typhoid and staphylococcus infections. Suppose 

 we have a case of furunculosis to treat. Enough work has been done 

 already on furunculosis so that we can be sure of obtaining a pure 

 culture of Staphylococcus aureus from the furuncles in our case and of 

 finding our patient's opsonic index low for that particular coccus ; we can 

 also be certain that the inoculation of half a billion to one billion dead 

 staphylococci of this strain would cause a rise in our patient's opsonic 

 index and at the same time the furunculosis would clear up. This being 

 the ease, it is necessary to obtain a tube of Staphylococcus aureus vaccine, 

 inject the proper dose, as given on the tube, and determine the result by 

 the progress of the case. 



Thus we see that the taking of the opsonic index is one separate 

 manipulation and the preparation of the vaccine is another, and the 

 only absolutely essential step in the treatment of any case of certain of 



