The Rot in Sheep. 
155 
is to be remembered that security depends iijjon the placing of 
sheep under circumstances wliich are calculated to pTcveiit the 
development of fiuhcs within their digestive organs. In other 
words, the encysted cercaricc must be either destroyed or expelled 
the system of the sheep before as perfected distomata they find 
their way into the biliary ducts. Prevention rests on this 
foundation alone, when the animals are so located that encysted 
ccrcaria; are day by day conveyed with the food into their 
stomachs. 
Another and equally sure way of preventing the disease -is 
doubtless to keep the sheep in those situations where, from the 
nature or improved condition of the soil, these penultimate forms 
of the fluke have no existence. This, however, cannot be done 
in many districts, especially in particular seasons ; for example, 
as the summer of 1860. So rife was rot in this year, in conse- 
quence of the excessive rainfall, that sheep took the disease on 
many farms where it had had no existence for a very long time 
before. Thus we see that in some localities rot is always to 
be met with, while in others it is only an occasional visitant. 
It persists in wet and undrained, or it may be in badly-drained 
land, independent of the state of the weather, becoming, of 
course, augmented in severity and more rapid in its progress in 
wet years than in dry. 
The improvements which are gradually, but far too slowly, 
being made by complete under-draining will do more on many 
larms to prevent rot than the driest season docs now to retard 
its protjiress, while on certain other farms it will exterminate the 
malady. In this respect under-draining becomes a national 
question, without reference to any other point, and if the wealth, 
of the country is to be maintained and food preserved to the 
people, every facility must be given to the effectual removal of 
all surface-water from our cold, retentive soils. Water must be 
made to percolate these soils, and yield the nutritive materials it 
holds in solution to the growing plants, instead of being left as 
now to stagnate on the surface — weakening vegetation, rotting 
sheep, and producing rheumatism and ague among our fellow- 
men. 
We speak from long experience in this matter, and also from 
the woful effects we have observed to attend the want of under- 
draining in the neighbourhood in which we dwell. The grass- 
lands of Middlesex, in the so-called Harrow district, the surface 
soil of which rests immediately on the London clay, are immensely 
lessened in value from this cause. Here rot persists, and here, 
as a consequence, instead of finding the meadows stocked with 
large and profitable sheep as meat-producing and wool-growing 
animals, we see them occupied with Welch and other mountain- 
