PHAGOCYTOSIS 291 



organisms into the peritoneal cavities of guinea pigs. Yet a chronic 

 tuberculous peritonitis or pleurisy is characterized usually by an 

 exudate which contains but few polynuclears and relatively many 

 lymphocytes. A final explanation of these conditions is not pos- 

 sible at present. No adequate explanation for the selective accu- 

 mulation of lymphocytes and the absence of polynuclear cells about 

 tuberculous foci has yet been advanced. The absence of polynuclear 

 leukocytosis may possibly be due to the great insolubility of these 

 bacilli, in consequence of which little or no leukocytosis-stimulating 

 substances are liberated. 



Pearce 39 has suggested a similar reason for the absence of poly- 

 nuclear accumulations about chronic localized lesions of any kind 

 in which tissue encapsulation may prevent the contact of the inciting 

 agents with the body fluids and there is a consequently slow or slight 

 production of such chemotactic stimulating materials. 



In typhoid f ever, where the slight primary leukocytosis is rap- 

 idly succeeded by a leukopenia with a relative lymphocytosis, the 

 conditions are somewhat different. Here, as in some other infec- 

 tions, as Friedberger and others have shown, we are dealing with a 

 generalized infection by an organism which is easily subject to the 

 action of alexin with consequent production of anaphylatoxin. (See 

 chapter on Anaphylaxis.) This poison, it seems, exerts a nega- 

 tive chemotaxis, and probably during the height of the disease, 

 therefore, leads to the low leukocyte count observed. That this is 

 at least likely seems to follow from the studies which have been 

 made upon the nature of the typhoid poisons, and also from the 

 observation of Gay and Claypole, that typhoid-immune rabbits react 

 to the infection of typhoid bacilli with a rapid and powerful increase 

 in the polynuclear leukocytes, whereas similar injections into the 

 normal animal lead to leukopenia. 



If the supposition regarding tuberculosis, made above, is correct, 

 it would follow that a sudden and considerable increase in the poly- 

 nuclear leukocytes in a case of tuberculosis would indicate a dis- 

 charge of organisms into the circulation and a tendency toward gen- 

 eralization of the infection in this manner. (See Weigert's view of 

 the manner in which tuberculosis may spread by the destruction of 

 the wall of a vein by a localized lesion.) However, although specu- 

 lation in the absence of experimental proof is justified, it must not 

 be forgotten that the problems of selective chemotaxis are too ob- 

 scure to permit of our laying much weight on any of these views. 



Gabritchewsky, 40 who investigated this subject extensively, has 

 classified various substances according to their positively, negatively, 

 or neutral chemotactic activities. It is not necessary to recapitulate 

 these, but it is interesting to note that he found that some substances 



39 Pearce. Jour. A. M. A., Vol. 61, 1913. 



40 Gabritchewsky. Ann. Past., Vol. 4, 1890. 



