THEIR CAUSES, NATURE, AND PREVENTION. 197 



when mature resembles a piece of white thread and the female 

 of which is about 1| to 2 inches long. It inhabits the wind- 

 pipe and bronchial tubes but its embryos gain access to the 

 deeper parts of the lungs and there set up much irritation and 

 patchy inflammation. 



In the lungs of thousands of sheep, not only native but 

 American also, killed in our slaughter-houses numerous small 

 nodules of a yellowish colour and about the size of a millet 

 seed are seen ; these have often been mistaken for tubercle 

 (consumption) but the microscope reveals the embryonic para- 

 sites in their interior. 



The development of the worm is not understood ; one thing 

 however is certain viz., that salt spread over the contaminated 

 pastures is a sure preventive ; drainage also is useful but sheep 

 should not, if it can be avoided, be put on infected fields. 



The lungs too of affected sheep should be destroyed instead, 

 as is often the case, being sold or used as food for people or for 

 cats. Cooking certainly kills the parasites if it is effectually 

 carried out. 



Many sheep suffering from hoose die from debility induced 

 by diarrhoea ; others die from suffocation and many from con- 

 gestion of the lungs, if exposed to a chill. 



Another round worm, the twisted strongyle (Strongylus con- 

 tortus), is often the cause of great loss amongst sheep. It is a 

 small worm like a piece of red thread and is found clinging, by 

 the aid of barbs, to the membrane of the fourth stomach, there 

 causing inflammation, diarrhcea, emaciation and death. 



It is most seen on old pasture land where there is plenty of 

 fog for cover and this fact points to the necessity of removing 

 the fog from such pastures by burning or by chain-harrows. 

 Top-dressing with lime or salt should also be practised. 



The only tape-worm of importance found in the sheep is the 

 Tmnia expansa, but it is questionable if it does much harm 

 and I have seldom found it unassociated with other parasites. 



In conclusion, I would say that no man can be a successful 

 sheep farmer unless he has some knowledge of the structure of 

 the animals he deals with (histology) or of the functions of 

 the different organs of its body (physiology) ; like the machinist, 

 he must not only make himself acquainted with the wheels and 

 pistons and cranks of his machine, he must know its every 

 fibre ; and even as machines are easily deranged so sheep are 

 " kittle cattle " ; no more delicate animal breathes. 



In addition to the above, the farmer must have a knowledge 

 of the chemistry as well as of the practice of agriculture and 

 if disease makes its appearance amongst his flocks he should 

 at once seek the aid of some one better versed in these matters 

 than himself 



