250 



THE ANIMAL PARASITES OF MAX 



domestic dog, the jackal, and the wolf, and is usually present in 

 great numbers. 1 The cysticercus stage (Echinococcus polymorphus) 



lives in various organs chiefly in the 

 liver and lungs of numerous species of 

 mammals (twenty-seven), especially in the 

 sheep, ox and pig, and it is even not un- 

 common in man, though the tsenia itself 

 has never been found in a human being ; 

 accordingly man can only acquire the Echi- 

 nococcus by ingesting the oncospheres of 

 the " dog worm." The dogs disseminate 

 the oncospheres of T. echinococcus wherever 

 they go, or carry them to their mouths 

 and coats by biting up the evacuated 

 segments, and are thus able to transmit 

 them directly to human beings (by licking 

 them or making use of the same crockery, 

 &c.). In other cases the oncospheres, 

 which are enclosed in a shell, must with- 

 stand desiccation for a time and then 

 (as when the dogs are " kissed " or 

 otherwise caressed) are transmitted into 

 or on to man. As echinococcus disease 

 ' in man is always very dangerous, it 

 would be a matter of general interest to 

 prevent dogs being infected by destroying 

 the echinococci, 2 and all measures would 

 be justifiable which would diminish the 

 superfluous number of house-dogs (for 

 instance, high taxes) ; measures should 

 also be adopted to limit the association 



coccus. 50/1. The cirrus pouch, of men with dogs, particularly in such 

 sh e e,l-gfa^ aT^eiS frequented places as restaurants, railway 

 gland, and the testicuiar vesi- carriages and tramcars. 



cles at the sides are recognis- 

 able in the second proglottis ; 

 the posterior proglottis shows 

 the uterus partly filled with 



eggs, as well as the cirrus ' In Iceland 28 per cent, of the dogs are infected 



pouch and the vagina. with this taenia, in Lyons j-\ per cent., in Zurich 3-9 



per cent., in Berlin i per cent., and in Copenhagen 



0-4 per cent. In Australia even 40-50 per cent, of the dogs are affected. It is, how- 

 ever, a question whether, in addition to T. echinococcus, a second analogous form is 

 not involved ; as the form from Canis dingo attains a length of 10 30 mm. 



- Mosler, F., " Ueb. Mittel z. Bekdmpfg. endem. vork. Echinococcuskrankh." 

 (Dlsche. Medic.-Ztg., 1889, No. 72). 



FIG. 175. Tcsnia echino- 



