268 ON THE SHEEP OF ZETLAND. 



Stevenson, I am inclined to believe, that inflamma- 

 tion had never existed. It is not a general quali- 

 ty of inflammation of the eye, which has proceeded 

 the length of f >nv t ing preternatural membranes, 

 to subside spontaneously in so short a time as a 

 fortnight, nor to be more readily removed when 

 the individual labouring under it is exposed to 

 light and air, than when secluded from their in- 

 fluence. 



In some of those lighter attacks, where a blue 

 film appears to cover the cornea, I presume that 

 the appearance is occasioned by the mere disten- 

 tion of the cornea ;om an increase in the quanti- 

 ty of the aqueous humour. This will produce 

 as perfect opacity as a membrane It appears 

 to be produced in the human species, and in horses 

 and dogs, by whatever tends to accelerate the mo- 

 tion of the blood to the head ; and analogy leads 

 me to think that it may also be a frequent cause 

 of temporary blindness among sheep. It is best 

 removed by a change of pasture, and repeated 

 doses of purgative medicines. 



The Scab was first introduced into the parish ( 

 of Dunrossness, the most southern district in the 

 country, about twenty-four years ago, by two 

 lambs sent from Scotland as a present to a gentle- 

 man, with a view of improving the breed of 



* A Treatise on the varieties and consequences of 

 Ophthalmia, p. 173, 



