The Rot in SJicq). 
W(! may horc leave the further consideration of this question 
for tlic present, to proceed with the history of the assigned 
causes. 
In the year succeeding the publication of Mr. Youatt's work 
a small manual on the diseases of sheep made its appearance, 
from the pen of Mr. A. Blacklock, surgeon, Dumfries. This 
gentleman strongly repudiated the opinion of entozoa being the 
cause of rot, and considered that it arose solely from tubercles 
located in the lungs. He remarks that " everything that has 
a tendency to weaken the animal will more or less lead to rot. 
Exposure to cold and wet, mishaps at lambing-time, food bad. 
in cpiality or deficient in quantity, and over-driving, will all pre- 
dispose the constitution to the deposition of tuhei-clcs." Here- 
after we shall have occasion to recur to the writings of Mr. 
Blacklock, and will only now incidentally remark that the so- 
called tubercles in the lungs of sheep have no pathological relation 
to those met with in cases of phthisis of man. Since the period 
at which this gentleman wrote, it has been ascertained that these 
deposits are produced by the well-known entozoon, the Filaria 
hronchialis. 
Subsequently to this date we do not find that any author of 
note has propounded any new views of the cause of rot. Mr. 
Spooner, of Southampton, however, after reviewing the statements 
of others, in his History, Structure, Economy, and Diseases of 
Sheep, 1844, remarks " it appears to me that in addition to 
the consumption of food in which water greatly abounds it is 
essential that this food should be in a state of decomposition 
(partially rotten) in order to produce the fatal disease." 
We come next to comment upon the general statements which 
have been made with regard to the pasturing sheep on Avater- 
meadows. It has long since been ascertained that during a 
certain period of the year sheep are sure to take the rot if placed 
on irrigated meadows, this being from about June to October. 
The cause of this is to our minds very evident ; but we must 
leave its explanation for the present, and reserve it for another 
section of our essay. 
Arthur Young, when speaking of watering meadows in his 
Farmer s Tour, vol. iii., says " that Mr. W. White, a tenant of 
Mr. Frampton's, of Moreton, Dorset, remarked, and it is the 
general observation of the country, that these watered lands never 
rot sheep in the spring, though they immediately follow the 
water, or are turned in at any time or in any manner ; but if 
they are turned into the after-grass, it rots till the autumnal water- 
ing, after which they are safe." 
Much has been said with regard to the draining and im- 
proving of twenty-five acres of imperfectly-made water-meadow 
G 2 
