OF SCOTLAND.

169

a very.common cause of rot, though the same effect wouldnot be produced by feeding on the same land, after beingflooded in spring. “ Mr Bakewell was of opinion, thatafter May-day, he could communicate the rot at pleasure, byflooding, and afterwards stocking his closes, while they weredrenched and saturated with moisture *and there aremany well-authenticated instances of the rot having been occa-sioned by a few minutes’ feeding on pastures in a similar state.It is on the circumstance of excessive humidity, accompaniedby exhalations raised in hot and sultry weather, that DrHarrison seems to found his hypothesis respecting paludaleffluvia being the cause of rot; but there is every reason tothink, that the rot is often engendered at a time when theweather is by no means so hot, merely by feeding on softmarshy pastures. The disease cannot be often ascribed toflooded lands in Scotland , where irrigation is but little prac-tised, and its mountain rivulets seldom overflow any con-siderable track on their banks, which are commonly steepand precipitous; or, when more level, kept under tillage ro-tations.

A course of changeable weather, fresh and frost alternate-ly, is certainly a frequent cause of the rot; and mild, rainywinters, when vegetation has been seldom checked by longcontinued frosts, are very dangerous to many of the moun-tain flocks, especially if vegetation has been unusually vigo-rous towards the end of autumn and beginning of winter.

With regard to the impregnated ova of insects being takeninto the stomach, it is observed, that fasciolae hepatic® aresometimes found in sheep that are not affected with the rot,and that in some instances no such insects could be discover-ed in the livers of rotten sheep. The process which the foodmust undergo in its several stages, after being brought upfrom the first stomach, seems to be a serious objection to this

* Harrison on the Rot, p. 36.