ON WOOD-EVIL AND MOOll-ILL. 623 
moor, or in the meadow, or elsewhere, it is essentially the same 
in its symptoms and progress. 
Wood-evil or Moor-ill . — This disease occurs in all seasons of 
the year, but is most prevalent in the summer, and especially 
when the season is dry. It is solely confined to certain dis- 
tricts, namely, moors and commons, and those abounding with 
wood, &c. 
Causes . — Farmers, who are occupying woody situations, and 
have this disease prevailing amongst their cattle, suppose it to 
proceed from these animals eating the leaves of some certain 
tree or trees ; or some of those plants which grow spontane- 
ously and very plentifully under the shade of trees : and on this 
account they designate it the wood-evil. On moors and com- 
mons, &c., where this complaint prevails, some of the farmers 
ascribe it to the hardness of the water, and others to the herb- 
age. It is for this reason that they term it the moor-ill. The 
fact is, that the causes of this complaint are very obscure. It 
does not proceed from a want of sufficient nutriment to supply 
the daily wants of nature, or it would be most prevalent on the 
poorest land, and in the winter season, when the provender of 
the cattle consists of little more than straw or very bad hay. 
This, however, is not the case ; for I am very well acquainted 
with several places where the land is extremely poor, and the 
animals half-starved during the winter season, and still they are 
perfectly free from this disorder. On the other hand, it occurs in 
certain places where the land is apparently good, and its pro- 
ducts plentiful, and there scarcely an animal escapes from its at- 
tack. It is not the effect of the animals eating of black willows, 
or crabs, or other trees possessing an astringent quality, or it 
would be oftenest found where these trees are most abundant, 
which is by no means the case. Cattle may now and then 
browse on the abovementioned trees, so as to become consti- 
pated, but I believe very rarely ; and even when this does hap- 
pen (if ever it does), it cannot be called any particular evil, for 
the laxative quality of the grass (if the season or situation ad- 
mits of its growth, or if the disease is not already existing in 
the animal) would speedily counteract the astringent quality of 
the crabs or willows, or, at most, a few Epsom salts would era- 
dicate the evil. I must say, that it has not the slightest con- 
nexion with the original meaning of its cognomen, wood-evil ; 
and where costiveness is once produced by eating crabs or 
willows, it arises five hundred times from other causes. My 
opinion is, that the natural and spontaneous production of some 
peculiar kinds of soil, and the water conjointly, are the chief if 
not the sole agents in the production of this disease. 
