378 Veterinary Medicine. 



Low Conditioti of the Lamb. Debility contributes to render 

 the lamb more receptive of the worm, and greatly lessens its 

 power to survive its attack, and in this way droughts with insuffi- 

 cient food encrease the mortality. 



Overstocking the pastures acts in the same way. The insuffi- 

 cient food causes low condition and weakness, and the necessity of 

 eating close to the ground, endangers the taking of the young 

 worms that are present on the vegetation near its roots and in the 

 adjacent moist earth. Overstocking further encreases the ova and 

 embryos in the soil. 



Dews and Showers cause the young worms to ascend higher on 

 the vegetation and to be taken in in greater numbers if the sheep 

 are left out over night, or turned out in the early morning or in 

 wet weather. In such cases there is always the added danger of 

 the grass coming up by the roots and being swallowed with the 

 verminous soil attached. 



Impaired health from previous or coexistent disease must always 

 be recognized as lessening the power of resistance. 



Worms in the bowels, liver or elsewhere are especially likely to 

 be present, and to contribute to encrease of mortality. 



Pasturing lam,bs in autumn on m.eadows occupied by infested 

 sheep in spring or summer, is one of the most common and danger- 

 ous practices, as the soil and water are then charged with the 

 young strongyli. 



Pasturing of sheep and lambs together on the same ground is 

 equally injurious. Youth is one of the mo.st powerfully predis- 

 po.sed conditions. I,ambs under a year old .show less resistance 

 and perish in far greater numbers than do the mature sheep. 



Common feeding or drinking troughs, especially the latter, may 

 become direct causes of infesting fresh animals, as the expecto- 

 rated embryos naturally fall in such places and after moulting 

 may be taken in by other animals. 



Lesions of Verminous Bronchitis in Sheep. Either of 

 the two strongyli described or both may be found in the bronchia 

 in an abundant muco-purulent secretion, and often rolled up in 

 bundles, which may block the lumen of the tube. The mucosa 

 of the affected bronchium is congested, reddened, thickened, with 

 its epithelium opaque, softened or even desquamating. The 

 bronchia may .show dilatations at intervals, filled with the vermin- 



