I20 



FOWL TYPHOID 



several cases, been suspected. From the appearances observed 

 in the red blood corpuscles it seems highly probable that 

 phagocytosis plays a comparatively large part in their destruc- 

 tion. Another hypothesis is also suggested, namely, that a 

 toxin produced during the multiplication of the specific organ- 

 ism has this effect 

 on the red corpus- 

 cles. In the fresh 

 preparations w e 

 can observe the 

 phagocytes attack- 

 ing the red cells. 

 In the stained ones 

 mutilated red cor- 

 puscles and free 

 nuclei are present. 

 The hypothesis is 

 suggested that the 

 leucocytes partially 

 Fig. 19. The phagocytic action of the white digest certain of 

 blood corpuscles upon the red ones in advanced the red corpuscles 

 cases. The changes represented fron i to g in their attack up- 

 took place in 35 minutes. ^^ them. ' Whether 



these changes are entirely attributable to the phagocytes 

 is an open question. 



In the blood from healthy fowls it is comparatively rare 

 to see one of the white corpuscles engulfing a red one. As the 

 disease progresses, however, this warfare becomes very con- 

 spicuous, owing perhaps to the increased number of the color- 

 less cells. Up to the present the study of these corpuscles has 

 not been extended beyond the observations of the general ap 

 pearance of these structures, and no attempt is made to explain 

 the apparently marvelous increase in the number of the leuco- 

 cytes. It is an interesting and as yet unexplained fact that 

 the increase in the corpuscles is apparently restricted to those 

 containing the spindle shaped bodies. 



§ 106. Differential diagnosis. Intestinal disturbances, 



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