172 



much larger than a millet seed. The abundance and size of the free 

 parasites Indicated that most if not all of them had developed in tlie 

 interior of the tube. The intestinal tumors indicated that there were 

 others developing in them. 



From the above it seems i^robable that this species develops nor- 

 mally in the intestine, that some of the young embryos penetrate into 

 the walls of the intestines, and at times even to the mesenteric lym- 

 phatic glands and elsewhere ; that those which penetrate into the intes- 

 tinal wall either develop very slowly or eventually die, depending on 

 the tissue penetrated and the favorable conditions the latter offer for 

 the nourishment of the parasite ; tbat those which develop slowly may 

 in time escape from the tumors and complete their development in the 

 intestinal canal ; that this phase of its life history may be one that is 

 favorable for the preservation of the species by preserving a few indi- 

 viduals in tumors throughout the winter which escape in early spring, 

 become adult, and lay their eggs, which are scattered on pastures favor- 

 able to the preservation of the embryos; that the majority of these 

 embryos, penetrating the intestinal walls, wander into such environ- 

 ments that they are eventually destroyed ; tbat this act of migration is 

 voluntary and only of benefit to the parasite when the latter becomes 

 lodged in the proper place, and that the same power which enables it 

 to arrive at these places also enables it to penetrate farther than is of 

 use to it; that the slow development of the worm in the tumors as 

 compared with the development in the intestine shows it to be a re- 

 tarded development, which may be hastened as soon as the parasite 

 again reaches the proper surroundings. 



In short, the fact of the intestinal life of these parasites is demon- 

 strated, as w^ell as the fact that some may wander into the intestinnl 

 walls and undergo a retarded development before re entering the in- 

 testine. 



The diagnosis of this parasitic disease can only be made from upost' 

 Dwrtem examination. In the living sheep there may be signs of general 

 debility — bloodless lips and eyes, thin sides and flanks, dry wool, etc. 

 It may be that nothing else will be noticed, but that the flock is not in 

 quite good condition ; or in sev^ere cases the diarrhea and emaciation 

 may be excessive. Dr. Salmon believes the disease may bring death to 

 its victims in the severest cases. My own observations have been con- 

 fined to the abattoirs, where salable animals only are brought. As the 

 adult worms arecomi>aratively few as compared with the tumors, it is 

 probable that the adults of this species cause but little trouble; but the 

 embryos, on the contrary, cause a great deal. The disease is an insidi- 

 ous one, for not only is the rate of infection gradual, increasing slowly 

 in amount from week to week, but the rate of development of the 

 'tumors is very slow, apparently requiring mouths. It is only when the 

 disease is well advanced that its cnn)ulative effects can be noticed. 



Tiie disturbance of digestion caused by this i)arasite is mainly due to 



