266 



ON THE SHEEP OF ZETLAND 



pasture of Zetland, there is not the appearance of 

 a flower in the course of many miles ; and the 

 few which do yield pollen, occur in the inclo- 

 sures, from which the sheep are carefully exclud- 

 ed during the summer. 



Mr Hog ascribes blindness to continued fatigue 

 and exertion, and endeavours to illustrate his opi- 

 nion by the examples of the affection occurring 

 in a severe degree in sheep that have been driven 

 a long distance to market. In the Zetland Islands, 

 sheep are never driven more than five or six miles 

 at a time, and that only with a view to assembling 

 them in a crue, for the purposes already men- 

 tioned. They are driven in the gentlest manner 

 on such occasions, and not a single instance of 

 blindness has ever been known to ensue from this 

 treatment. 



That the different exciting causes enumerated 

 by these gentlemen, when applied in sufficient 

 force, may produce inflammation of the eyes, I 

 have little doubt ; but they must be considered 

 as being purely local and adventitious, and can 

 never be supposed to exert an influence beyond 

 the scene of their immediate action. In the Zet- 

 land Islands, they are not known to operate, and 

 yet a general disease exists, which exhibits, in its 

 commencement and progress, a train of symptoms 

 similar to that which characterizes the affection 

 which has been ascribed to their presence. 



These considerations lead me to conclude, that 

 the belief in ?,etland ; that blindness was origi- 



