CESTODES 1 '4 1 



produces pruritis ami otluu- aiiapliylactic symptoms, and altliouf^h the 

 serum of sheep with this parasite does not confer passive anaphylaxis 

 to sarcosporidia, yet it does give positive complement fixation." That 

 it is a true toxin is shown by Tcichmann and Braun,-** who produced 

 an effective antitoxin by immunizing rabbits; only rabbits seem to 

 be susceptible to the toxin. The sarcosporidia contain also a distinct 

 thermostable agglutinin. The lethal dose of dried substance of sar- 

 cosporidia is, for rabbits, but 0.0002 gm., and the poison seems to unite 

 with the lipoids of the nervous system (Teichmann).^^ It is probable 

 that the pathogenic protozoa, at least in some instances, have a semi- 

 permeable membrane about them, for GoebeP'' found that trypano- 

 somes are very susceptible to changes in osmotic conditions. 



rCESTODES] 



Taenia echinococcus has been by far the most studied, its abundant 

 fluid content furnishing suitable material for investigation. That 

 this fluid is toxic has been repeatedly observed when, through rup- 

 ture or puncture, the fluid has escaped into the body cavities; such 

 accidents are often followed by violent intoxication, sometimes by 

 death. 3^ As long as the cyst is unopened no toxic manifestations are 

 observed. The most constant symptoms are local irritation and in- 

 flammation, accompanied by urticaria, which may also be produced 

 experimentally in man if the cyst contents are injected subcutaneously. 



The symptoms are so strikingly similar to those of anaphylactic 

 intoxication, that it is now generally believed that they are the result 

 of such a reaction in a person sensitized by absorption of antigenic 

 substances from the cyst.^^ Carriers of echinococcus cysts have been 

 found to have in their blood antibodies giving precipitins^ and 

 complement fixations'* reactions with extracts of echinococcus, and 

 sometimes with other taenia. ^^ The antigen of the echinococcus is be- 

 lieved by some to be a lipoid ;S6 in the case of Taenia saginata, at least, 

 it seems to be associated with the lecithin (JMeyer^^). Graetz," 

 however, states that the protein of the hydatid cyst is derived from 

 the host, and that it is therefore incapable of causing anaphylaxis in 

 that host, but it may undergo alterations in the cyst so that it is 

 toxic after the order of anaphylatoxins (q. v.) . The complement fixa- 



" McGowan, Jour. Path, and Bact., 1913 (18), 125. 



28 Arch. f. Protistenk., 1911 (22), 351. 



" Ibid., 1910 (20), 96; see also Knebel, Cent. f. Bakt., 1912 (66), 523. 



30 Ann. Soc. Mrd. d. le Gand, 1906 (86), 11. 



3' See Achard, Arch. gen. de Med., 1887 (22), 410 and 572. 



^^ See Boidin and Laroche, Presse Med., 1910 (18), 329; Ghedini and Zamorani, 

 Cent. f. Bakt., 1910 (55), 49. 



" Welch, et a/., Lancet, 1909, Apr. 17. 



" Kreuter, Miinch. med. Woch., 1909 (56), 1828; Weinberg, Ann. Inst. Pasteur 

 1909 (23), 472. 



3^ Meyer, Berl. klin. Woch., 1910 (47), 1316; Zeit. Immiinit.nt., 1910 (7), 732. 



3« Israel, Zeit. Hyg., 1910 (66), 487; Meyer, Zeit. Immunitat., 1911 (9), 530. 



3' Zeit. Immunitat., 1912 (15), 60; general review. 



