The Leech. . 541 
any food. It is usual, however, to make them disgorge 
the greater part of the blood they have swallowed by 
sprinkling them with salt ; as otherwise they would 
not bite again till the blood they had taken was fully 
digested. 
Leeches lay eggs, which are covered with a kind of 
membrane, which serves to protect them when they are 
deposited in the clay and holes in the sides of ponds. 
They appear to live on the eggs of fish or frogs, but 
eagerly attach themselves to the legs of human beings, 
horses, or cows, whenever they have an opportunity. 
As there is a prejudice among the country people that 
Leeches never breed well till they have tasted blood, 
it is said that they drive their horses and cows into the 
water inhabited by the Leeches, and consequently that 
the Leech districts are remarkable for their wretched- 
looking horses and cattle. Leeches must be five years 
old before they are fit for medical purposes ; and they 
are caught in shallow water in spring by people going 
in with naked feet and ankles, to which the Leeches 
adhere, when they are picked off and put in baskets 
provided for the purpose. In summer a raft is made of 
twigs, and the waters being disturbed with a stick, the 
Leeches rise to the surface, and get entangled in the 
raft. When caught, they are washed in water with a 
very little salt in it, and packed in wet linen cloths, 
which are put into a barrel with a canvas cover, and 
sent away for sale. London used to be chiefly supplied 
from the fenny districts of Lincolnshire, but the con- 
sumption of these useful worms has been so great that 
most of our Leeches are now imported through Hambro' 
from the east of Europe. Some years since Dr. Pereira 
stated that the number of Leeches imported by the four 
principal dealers in London amounted to 7,200,000 
annually. They are also, when kept in a glass bottle 
with water, a good barometer, as they always come up 
to the neck of the bottle when rainy weather is ap- 
proaching, remain at the bottom in dr}>- weather, and 
move anxiously up and down when the weather is 
stormy. Horse-Leeches are larger than the common 
species, more voracious, and narrower at each extremity. 
