OPSONINS IN TUBERCULOSIS 303 



The object of a vaccination is thus to supply this deficiency. 

 If it is successful, the focus is flooded with lymph rich in opsonin 

 and the bacilli are consequently phagocyted and destroyed. The 

 reaction of the opsonin-producing mechanism is, however, not a 

 simple one, and Wright has adduced evidence that as in the in- 

 troduction of other antigens, the injection of tuberculin is followed 

 by a period, normally lasting a day or two, when the amount of 

 opsonin is actually lower than it previously was (occurrence of 

 negative phase). This, in a successful vaccination, is followed 

 by a rise in opsonic content of the serum to a point above the 

 level existent at the time of injection (production of positive 

 phase). In certain cases a positive phase is easily obtained ; in 

 other cases there is a tendency to a prolonged persistence of the 

 negative phase, and if during such an occurrence a fresh tuber- 

 culin injection be produced, a still greater fall in opsonic content 

 may occur, usually accompanied by clinical exacerbation of the 

 tubercular symptoms. It is thus, in Wright's view, necessary to 

 follow the course of a tuberculin immunisation by frequent, it 

 may be daily, observation of the opsonic index, so that succeed- 

 ing vaccinations should only be practised during positive phases. 

 Immunisation is further complicated by the fact that there is a 

 variable and often uncontrollable absorption into the body from 

 the focus of infection of what is really tuberculin derived from 

 the disintegration of the infecting bacilli. The treatment is 

 thus interfered with by the superimposition of positive and nega- 

 tive phases produced by such autoinfections without purposive 

 qualities. This, according to Wright, renders the constant 

 observation of the opsonic index all the more necessary. The 

 laborious nature of the opsonic technique, however, makes it 

 impracticable to control every immunisation by its use, and the 

 application of this control must probably be reserved for the 

 more serious cases. In chronic long-standing affections the 

 observation of the clinical effects of the treatment is probably 

 sufficient. 



Antitubercular Sera. From what'^has been said regarding immunity 

 reactions in tuberculosis it will be gathered that it is questionable whether 

 the use of passive immunity in the treatment of tuberculosis has a rational 

 basis. Several investigators, however, have introduced the sera of animals 

 treated with the products of tubercle bacilli for therapeutic purposes. 

 Amongst these are Maragliano, who has treated dogs, asses, and horses 

 with materials derived from the tubercle bacillus, and administers their 

 serum in doses of 2 c.c. every two days in human tuberculosis. An anti- 

 tubercular sera has also been introduced by Marmorek, who grows the 

 bacilli in media unfavourable to their vitality and employs such growths 

 for immunising animals whose serum he states is suitable for the treat- 

 ment of human cases. 



