213 DISEASES DUE TO INTERNAL PAEAjSITES. 



The strongjlus filaria in length is from one to two and a 

 half inches long, in color the male is a brownish yellow, and the 

 female white, their bodies are uniform throughout their entire 

 length, except at the ends, which are tapering. "The head is 

 short, stumpy, rather angulai', 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." — 

 Williams. 



In aged sheep these parasites do not always cause incon- 

 venience, as an examination of the lungs of fat sheep has shown 

 them to be loaded with these worms; but in lambs the parasites 

 pierce the softer lung-tissue, gaining entrance to the bronchial 

 tubes, where they set up an intense irritation, frequently caus- 

 ing death. While aged sheep are not so liable to show the effects 

 of attacks from these parasites, sometimes they become anaemic 

 and debilitated, especially is this noticeable in lambing ewes, 

 many of which succumb to the trouble. These parasites in 

 sheep are the cause of bronchitis and sometimes pneumonia, and 

 very often a combination of the two called broncho-pneumonia. 



The method of their introduction appears to be through the 

 medium of the water supply, or from grasses, especially those of 

 low-lying lands having an insufficient drainage. On gaining 

 access to the alimentary canal (stomachs and intestines) they 

 pierce the walls of these viscera and obtain entrance to the circu- 

 lation, by which they are carried to the lung tissue, where they 

 remain till mature, when they pierce the tissues and pass into 

 the bronchial tubes. Their presence then sets up the irritation 

 characteristic of the disease, the parasites remaining in the lung 

 tissue outside of the tubes, appearing to .cause little if any incon- 

 venience. Williams states that he has observed these parasites 



