PHAGOCYTOSIS 277 



It is on these facts that Wright's vaccine therapy, or, as it is 

 sometimes called, opsonin therapy, is based. The object of the 

 treatment is to bring about an immunization of the patient by 

 means of an increase of the opsonin circulating in his blood, and 

 this is achieved by the injection of a suitable vaccine. This con- 

 sists in all cases of the dead bodies of the bacteria causing the 

 disease. In the case of tubercle Koch's new tuberculin (TR 

 or TE) is used in variable amount, but not usually more than 

 j-^0- milligramme of dry material per dose. In the case of other 

 bacteria the vaccine is prepared by cultivating the organism on a 

 suitable solid culture medium, emulsifying with normal saline 

 solution, and heating to a temperature just sufficient to insure 

 sterility usually 60 C. for one hour is requisite. The emulsion is 

 then inoculated on to a culture medium, incubated in order to test 

 its sterility, and the number of bacteria which it contains is counted, 

 in order to determine the amount to be used as a dose. Suitable 

 dilutions are then made. The dose varies with different bacteria. 

 Thus, with staphylococci 250,000,000 to 1,000,000,000 cocci may 

 be given, whereas with B. coli 25,000,000 is usually enough for 

 the first dose. 



The treatment is controlled by a frequent estimation of the 

 opsonic index, and this is supposed to be advisable for three 

 reasons : (i) It avoids the possibility of a summation of the 

 negative phases, and so a worsening of the patient's condition by 

 lowering his immunity to the infective organism. As a rule, the 

 negative phase is but of short duration, but occasionally it is pro- 

 longed, and this is especially the case when large doses have been 

 given. I have seen it as long as three weeks in a case of tubercle. 

 (2) It enables a suitable dose to be selected. Thus, if we find a 

 certain number of bacteria cause a long negative phase, the next 

 injection should consist of a smaller one, when the negative phase 

 may be reduced and the rise may be greater. With a very small 

 dose the negative phase may be eliminated altogether, or may be 

 reduced so much that it is overlooked. (3) Whilst the index is 

 raised decidedly above normal it is assumed that the patient is 

 benefiting, and another injection is only required when it begins 

 to fall. As a rough general rule, the injections have to be repeated 

 at intervals varying from a week or fortnight, but individual 

 patients show decided differences in this respect. 



Of the practical success of this treatment in certain diseases 

 there can be no doubt, and whatever we may think of its theoretical 



