PHENOMENA FOLLOWING IMMUNIZATION 101 



the animal body is subjected to any one of the processes spoken of as 

 immunization. The exact location of the antibody-forming cells and 

 tissues, in spite of much investigation, is not at all clear, though 

 many data seem to point to the lymphatic organs, the spleen, and the 

 bone marrow as particularly concerned with this process. 



Thus Pfeiffer and Marx ' 9 exsanguinated animals five days after 

 injections of dead cholera spirilla and found that at this time bac- 

 teriolytic antibodies were more concentrated in the spleen than in 

 the blood serum itself. Wassermann's 80 analogous experiments with 

 typhoid bacilli seemed to show a higher antibody content in spleen, 

 bone marrow, thymus, and lymph nodes than was present in the 

 blood at an early period of immunization. Although these investiga- 

 tions, as well as many others of Castellani, 81 seem, therefore, to indi- 

 cate a particular association of the special lymphatic organs with 

 antibody formation, 82 extirpation of the spleen 83 before immuniza- 

 tion has not prevented animals from responding to injections of bac- 

 teria and red blood cells with sharp antibody production. The ex- 

 periments of Deutsch, 84 in which reduction of antibody formation 

 resulted in animals in which splenectomy was practiced three or four 

 days after immunization was begun, can hardly be accepted as a con- 

 clusion, in the writer's opinion at least, since any severe operation or 

 interference with the normal functions of an animal during the 

 severe physiological strain of active immunization would naturally 

 lead to a less perfect response. That the resistance of animals and 

 man to infection with bacteria is not noticeably diminished by sple- 

 nectomy, moreover, has been variously shown. In unpublished ex- 

 periments by the writer splenectomized guinea pigs showed no differ- 

 ence from normal animals in regard to their susceptibility to tuber- 

 culosis. And though these and similar experiments of other workers 

 with various bacteria are not entirely devoid of interest, their nega- 

 tive results as a matter of fact have no great significance, since our 

 knowledge concerning the true function of the spleen is very incom- 

 plete, and it is not impossible that on removal of this organ other 

 elements of the lymphatic system may take over its function in part 

 or as a whole. 



Removal of the spleen has not been an extremely unusual pro- 

 cedure in surgery, and there is no evidence to show that patients so 

 treated have been abnormally susceptible to infection thereafter. 



Yet, as we have seen, there seems to be an early concentration of 

 antibodies in the lymphatic-e^gftBs in the course_jof -immunization, 

 and it may well be that an association between the process and these 



79 Pfeiffer and Marx. Zeitschr. f. Hyg., Vol. 27, 1898. 



80 Wassermann. Berl. klin. Woch., p. 209, 1898. 



81 Castellani. Zeitschr. f. Hyg., Vol. 37, 1901. 



82 Pfeiffer and Marx. LOG. cit. 



83 I. Levin. Jour. Med, Res., Vol. 8, 1902. 



84 Deutsch. Ann. de I'Inst. Past., Vol. 13, 1899. 



