SANDY ISLE. DISEASES OF THE HIGHLANDS. 467 



from which they could have derived their origin; while 

 they are far too large to have been accidentally trans- 

 ported as ballast, or brought intentionally for building. 

 The rock of which they consist is that which forms so 

 large a portion of Rum, and of Sky. They may possibly 

 have been transported from the former of these islands 

 before those changes of the surface had taken place of 

 which there are not wanting abundant indications over the 

 whole globe. It is however more probable that they have 

 been derived from portions of the conglomerate rocks 

 formerly described, at a period when these occupied a 

 greater space than they do at present ; the most durable 

 substances remaining thus insulated, while the cementing 

 trap has mouldered into soil. 



WHILE detained by gales of wind in the harbour of 

 Canna I had an opportunity of observing the characteristic 

 veneration which the Highlanders possess for medicine ; 

 proportioned, as it would seem, to the scarcity of its pro- 

 fessors. It would be unpardonable not to bestow a cursory 

 notice on the diseases of the Highlands ; since they form 

 a frequent object of inquiry among those who have com- 

 paratively few opportunities of being informed respecting 

 them. 



Fever rarely now visits this country, although, by all 

 concurrent testimony, once prevalent and fatal. The 

 change cannot be attributed to superior cleanliness or 

 comfort ; as in these respects the houses have undergone 

 no change, and the inhabitants but little : it doubtless 

 originates in the more ample supply of food ; the con- 

 tagion appearing, in all the recorded instances, to have 

 been generated after seasons of scarcity ; a cause of fever 

 well known to physicians. But I must remark that it 

 has within a few years found its way with renewed severity 

 into some of the most improved districts on the borders 

 of the Lowlands; the consequence, it is to be feared, 



