ON LEECHES. 
115 
drink, and so easily as is believed — as nothing proves they may be 
able to fix themselves on the mouth with great promptitude — I must 
admit that they have never caused any accident, since, during the 
whole time I remained in Spain, I never heard of any unpleasant- 
ness of that nature, neither did I ever see any horses affected by 
morbid pains which could be attributed to them. 
What may have given rise to the idea, which from my obser- 
vations I must regard as an error, that leeches can live and re- 
main as long in the nasal cavity as they can in the mouth of the 
horse,, is, that those of the animals who have leeches in the nasal 
cavity, besides the flowing of blood which they cause on the lips 
and chin, are also afflicted with nasal haemorrhage, similar to that 
which the leeches produce when they are lodged for a moment in 
the cavities of the nose ; but the blood which forms these nasal 
haemorrhages almost always comes from the mouth. The blood 
which has been disgorged by the leeches goes to the back part of 
the mouth, and, not being all swallowed by the horse, part of it 
runs off through the exterior orifices of the air-passages. In these 
cases, however, the nasal haemorrhage only lasts as long as the 
leeches remain in the horse’s mouth, and it ceases without any sort 
of attention as soon as he gets rid of them. It was after con- 
stantly seeing this fact verified that I came at length to the cer- 
tainty, that leeches can neither live nor remain so long in the nasal 
cavities as in the mouth. Besides, these nasal haemorrhages caused 
by leeches in the mouth are seldom so abundant. The blood of 
which they are formed is black. It is not pure ; it is mixed with a 
certain quantity of saliva, and forms a bloody tract, which colours 
the pituitary and the inferior part of the nasal canal, and dries up 
the orifice of the nose. 
After what I have said on the effects of leeches and the evils 
they cause to those horses in whose mouths they are established, 
it will easily be perceived that we ought not to delay to get rid 
of this host of true parasites. 
Generally it is easy to discover the leeches that are in the 
mouth, especially when there is a great number of them, or when 
they are tolerably large; but sometimes it requires very great 
attention to discover the place which these reptiles occupy, espe- 
cially when the membrane is black or strewed with black patches, 
as it sometimes is in the horse. At other times, and particularly 
when they are small, they may escape the first search, by getting 
behind some of the folds of the membrane or under the tongue. 
The Spaniards employ divers means to make the leeches which 
are fixed in a horse’s mouth dislodge themselves ; such as water 
saturated with muriate of soda,” oil, or, above all, a decoction of 
tobacco. I have never made use of any of them for leeches which 
