130 CHEMISTRY OF THE ANIMAL PARASITES 



number of parasites present in the tissues at once. That the 

 eosinophilia is due to the action of the soluble products or con- 

 stituents of the parasites has been shown by experimental injec- 

 tion into animals of extracts from the bodies of the parasites. 1 

 Calamida has found that extracts of dog tapeworms also, when 

 placed in the tissues in a capillary tube, cause an accumulation of 

 eosinophile cells in the tube. Experimental infection with exces- 

 sive numbers of trichinella causes a rapid diminution in the number 

 of eosinophile leucocytes, which also show evidences of disinte- 

 gration in the bone-marrow and lymph-glands. Such large 

 injections are fatal, which suggests that the eosinophilia has a 

 protective influence. In favor of this view is the observation 

 of Milian, 2 who found that sarcosporidia in beef are destroyed 

 by a violent leucocytic reaction, the prevailing cell being the 

 eosinophile. As the eosinophile increase does not occur until 

 several days after the infected flesh is eaten, the chemotactic 

 substance is not liberated from the encapsulated trichinellse when 

 their capsules are digested off in the gastric juice, but comes 

 either from the free larvae, or from the degenerated muscles in 

 which they burrow. Coincident bacterial infection may reduce 

 the number of eosinophiles. 



PROTOZOA 



These unicellular forms possess all the chemical characters 

 of the cells, of higher forms, even to the more specialized con- 

 stituents. Thus it has been demonstrated that protozoa contain 

 proteolytic enzymes, 3 and that they secrete an acid into their 

 digestive vacuoles. 4 On the other hand, Amoeba coli does not 

 seem to digest the red corpuscle and the bacteria that it takes 

 up. 5 Whether the Amoeba coli produces any toxic materials, 

 specific or non-specific, has not yet been determined, but the 

 necrosis that it produces in liver abscesses, when bacterial co- 

 operation can often be excluded by culture, strongly indicates 

 the production of necrogenic substances. Apparently these sub- 

 stances are not chemotactic, in view of the absence of leucocytic 

 accumulation which is characteristic of the lesions of amebic 



1 If Habershon's views (Jour. Pathol. and Bacteriol., 1906 (11), 95) on the 

 relation of glycogen to the eosinophile granules is correct, it is possible that 

 there exists some relation between the abundance of glycogen in the animal 

 parasites and their tendency to cause eosinophile accumulations. 



2 Bull, et Mem. Soc. Anat., 1901 (Ser. 6, T. 3), 323. 

 3 Mouton, ComptRend. Soc. Biol., 1901 (53), 801. 



*Le Dantec, Ann. Inst. Pasteur, 1890 (4), 776; Greenwood and Saunders, 

 Jour, of Physiol., 1894 (16), 441. 



5 Musgrave and Clegg, Bureau of Gov't. Laboratories, Manila, 1904, No. 18, 

 p. 38. 



