PROTOZOA 1 29 



tiichinellac when their capsules are digested off in the Kiistric juice, hut comes either 

 from the free larv;r, or from the dcRcncratcd muscles in wliich ihey burrow. 

 Coincident bacterial infection may reduce the number of eosinopliiles. Ilerrick^ 

 finds that extracts of Asciiris Imnbricoidcs cause a notable eosinophilia, but only 

 \vh(m tlio aninuil has been sensitized previously with the same extract, tiie active 

 aKcnt of which is a protein; this suggests a relationship between i)arasitic and ana- 

 phylactic eosinoi)hilia.' That the eosinophilos i)lay a i)art in the immunity 

 reactions observed in the hosts of animal parasites is indicaterl by the fact that 

 hydatid fluid loses its antigenic pr()])erti(>s when in contact with eosinopliiles.* 



PROTOZOA 



These uuicellular I'orins possess all the chemical characters of the 

 cells of higher forms, even to the more specialized constituents. Thus 

 it has been demonstrated that protozoa contain proteolytic enzymes,'" 

 and that they secrete an acid into their digestive vacuoles. '^ On the 

 other hand, Amoeba coll does not seem to digest the red corpuscles and 

 the bacteria that it takes up.'^ Whether the Amceha coli produces 

 any toxic materials, specific or non-specific, has not yet been determined, 

 but the necrosis that it produces in liver abscesses, when bactewal 

 cooperation 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 ac- 

 cumulation in the lesions of amebic dysentery'. There is also no 

 evidence, clinical or experimental, that amebic infection causes the 

 formation of anti-substances of any kind in the body of the host. 

 The spontaneous recovery from amebic and other protozoan infections, 

 however, may be considered as indicating the development of an 

 immunity against these organisms.'^ Numerous observers have sug- 

 gested the possibility of obtaining artificial immunity against pro- 

 tozoa, and Rossle'^ has obtained immune sera against infusoria. 



The serum of rabbits immunized against amoebae was foimd b}' 

 Sellards'^ to be cytolytic for the same amoebae, but no antibodies 

 could be foimd in the blood of patients with amebic dysentery. The 

 serum of persons infected with bilharzia is said to give specific com- 

 plement fixation reactions (Fairley) . ^^ Novy '^ has obtained immunity 

 against trypanosomes, but the serum of immune animals will not 

 confer passive immunity. Braun and Teichmann,'^ however, claim 



^ Arch. Int. Med., 1913 (11), 165. 



» Supported by Paulian, Presse Med., 1915 (23), 403. 



^ Weinberg and Seguin, Ann. Inst. Pasteur, 1910 (30), 323. 



"> Mouton, Compt. Rend. Soc. Biol., 1901 (53), 801. 



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

 of Phy,siol., 1894 (16), 441. 



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

 p. 38. 



'^ Concerning immunity to protozoanjinfections see Schilling, KoUe and Wasser- 

 mann's Handbuch, 1913 (7), 566. 



'^ Arch. f. Hyg., 1905 (54), 1; full review of this topic. 



'5 Philippine Jour. Sci., 1911 (6). 281. 



'» Jour. Kov. Armv Med. Corps, 1919 (32). 449. 



'"Jour. Infec. Dis., 1912 (11), 411. 



'« Zeit. Immunitat., Ref., 1912 (6), 465. 

 9 



