JOINT-ILL. 221 



Vague references have now and again been made to here- 

 ditary influence, but no data are forthcoming to establish it as 

 a factor in the induction of the disorder. Nor is there any 

 reason for regarding it, as some have done, as a contagious 

 affection. 



Gamgee found that flocks affected with this disease " had 

 been kept in a confined space in winter, had been fed well, 

 and not allowed to move about sufficiently." In our own 

 experience this has not been the case. We have seen it in 

 open folding with plenty of room to " fall back," but where 

 the food was confined exclusively to roots until a short period 

 before parturition. It has mostly been the case that the roots 

 have been of indifferent quality and much diseased, and the 

 ewes in low condition when brought into the lambing pens. 



Without ascribing the disease altogether to a state of 

 debility, such as an exclusive diet of indifferent roots may 

 induce, we are strongly impressed with the importance of this 

 condition as a predisposing influence, leading, as it must, to a 

 general debility and constitutional impairment of the foetus. 



For a better understanding of the exciting cause, we turn to 

 the state of the navel, where we usually find more or less 

 swelling, or some imperfect closure of the orifice, or an abscess, 

 or a soft putrefying blood clot occupying the mouth of the vein 

 which in the foetus passes from the umbilical orifice to the 

 liver, and there is every reason for the belief that the in- 

 complete closure of this foetal orifice, arising out of an in- 

 differently nourished organism, serves as a channel through 

 which matter of a putrefactive character gains access to the 

 circulation, and, settling down in the joints and other organs 

 of the body, excites in them inflammation and abscess. Hence 

 the disease has come to be regarded as a state of pyaemia or 

 poisoning of the blood through the imperfectly closed and 

 diseased navel opening. This view of the pathology of the 

 affection seems to explain much, both in the symptoms 

 exhibited during life and the changes observed after death, 

 which could not otherwise be accounted for. 



