WORMS. 
143 
small semi-oval tubercles arranged in a triangle, the upper 
edge of each tubercle being cut into minute but sharply 
serrate teeth. When a vacuum is made beneath the an- 
terior sucker, these tubercles are brought into close con- 
tact with the skin of the patient : proper muscles then 
move them to and fro in a saw-like fashion, when the 
minute teeth presently cut through the skin and superfi- 
cial vessels, and the blood flows profusely, under the at- 
mospheric pressure, into the stomach of the Leech. 
It is very remarkable that blood is not the natural food 
of the Leech ; and that the fluid which it so greedily 
swallows does not pass into the intestine, but remains in 
the stomach for many months ; and, what is still more 
curious, it does not coagulate during tho whole of that 
time, as it would do in an hour if exposed to the air, but 
continues to retain its fluidity. Hence it has been not 
unreasonably concluded that this habit is rather a special 
provision ordained by the Divine mercy to render these 
creatures subservient to the alleviation of human suffering 
than necessary to supply the wants of the animals them- 
selves. 
We must not, however, suppose that the “ convenience, 
health, or safety” of man is the only object' of the crea- 
tive wisdom of God. There are numberless provisions 
expressly made for the comfort and wellbeing of the in- 
ferior creatures themselves ; and no creature is so mean, 
worthless, or humble, but it has been tho object of His 
paternal care in multitudinous instances, a few of which 
only, doubtless, we are cognisant of. Two or three ex- 
amples of benevolent foresight and curious contrivance 
have been mentioned in this paper, and tho enumeration 
