CHAPTER LXXIV. 



PAEASITIC DISEASES— continued. 

 DISEASES CAUSED BY NEMATODA OE EOUiND-WOEMS. 



PARASITIC DISEASE OF THE LUNGS. 



In the calf and lamb, broncliial irritation, arising from the pre- 

 sence of nematode parasites, termed strongyles, is of frequent 

 occurrence, and is variously termed The Husk, Hoose, Phthisis 

 'pulmonalis verminalis, and Parasitic hronchitis. 



In the lamb, the parasite, termed Strongylus filaria, is from 

 one to two and a half inches long ; the female is white, larger 

 than the male, which is of a yellowish-white colour, and its 

 body is of uniform size, but tapered at both ends. The head is 

 short, stumpy, rather angular, but not tuberculated as in other 

 strongyles. Extending from the mouth is a short oesophagus, 

 entering the stomach, from which a straight intestine is con- 

 tinued nearly to the extreme end of the tail. The tail of the 

 female is pointed ; the oviducts, filled with eggs and live young, 

 extend into the vulva, which is situated close to the anus. 



The anatomical situation of the parasites in the lungs of lambs 

 and sheep is not always the same. In lambs they are found 

 not only in the bronchial tubes, but also in the lung-substance, 

 whilst in sheep they are generally encysted in the parenchyma 

 of the lungs, giving them the appearance of being filled with 

 small tubercular deposits ; indeed, the disease was for a long 

 time looked upon as a true tubercular affection. I am of opinion 

 that within the last few years the disease is more commonly met 

 with, and during the winter and spring of 1873-1874 I had 

 more opportunities of witnessing it than in any former years. 



The lungs of sheep which have been the hosts of these para- 

 sites are thickly covered with numerous small nodules, varying 



