640 Abstract Report of Agricultural Discussions. 



is often accompanied with diarrhoea. In cases where there has not 

 been a healty and perfect decarbonisation of the blood, from struc- 

 tural disease of the lungs, diarrhoea often results. Take, by way of 

 illustration, that disease which in the human subject is known by the 

 name of i^hthisis. It is well known that some persons who are at- 

 tacked by this disease have diarrhoea, and when the disease tends to a 

 fatal termination the diarrhoea becomes very copious, and life is some- 

 times sacrificed through the depression of the animal powers thus 

 produced. Nevertheless, the origin of the diarrhoea is disease of the 

 lungs, which prevents them from performing their i:)roper functions, 

 viz., the proper decarbonisation of the blood. This accounts to some 

 extent for the presence of diarrhoea in sheep. 



The Filaria Bkonchialis. 



Now, this filaria hroncMalis is a worm, which I am justified in 

 saying is somewhat on the increase. We can readily imderstand why 

 it should be so : for although we really know very little of the natural 

 history of the worm, or of the best means at our disposal for getting 

 rid of it, we can see the likelihood of the afiection passing from sheep 

 to sheep, and from farm to farm. So long as we are unable, through 

 studying their natural history, to get rid of these worms before they 

 pass into the organism of the sheep, so long shall we be contending 

 with a disease which is in reality om- master ; and we may therefore look 

 for a great increase of cases of this kind. With regard to the circum- 

 stances which favour an attack, it is rather remarkable that though on 

 no description of land is there absolute immunity, yet sheep kejit in 

 open light-land districts are far less frequently attacked than those 

 kept in enclosed spaces, and particularly sheep which are kept at that 

 particular period of the year already alluded to in parks. With re- 

 ference to the worm itself, it would appear that even if only one or 

 two of the worms, being of diflerent sexes, find their way into the 

 bronchial tubes, that would be quite sufficient to lay the foimdation 

 for extensive disease of the lungs. They lay this foundation by tra- 

 velling as far as they can through the bronchial tubes (which are con- 

 tinuations of the windpipe) into the very air-cells of the lungs, where 

 they deposit their ova. As the result of that deposition of ova, which 

 may be said to be in myriads, irritation is set up first in the lining 

 membrane of the air-cells, which extends to the parenchyma of the 

 lung. The lung then imdergoes a peculiar change : it becomes altered 

 in colour, it will sink in water, and, as an aerifying organ, it is in 

 many parts altogether destroyed. This often takes place, particularly 

 on the fringe or edge of the lung, but not unfrequcntly in other por- 

 tions. The brood of young worms is hatched absolutely in the bron- 

 chial tubes and in the air-cells of the lungs •, so that the large quantity 

 of these worms which are frequently met with in the bronchial tubes 

 did not enter from without, but were produced within. These crea- 

 tures may, so far as their immediate develojiment is concerned, be 

 termed ovo-viviparous — that is to say, a great number of eggs will bo 

 thrown out as eggs ; but frequently the young worm will escape from 

 those eggs while yet within the parent. In making a section of the 



