THE LEECH. 



467 



ties. Though with us there are insects some- 

 what resembling them in form, we are placed 

 at a happy distance from such as are really 

 formidable. With us they seldom grow above 

 an inch long ; in the tropical climates they are 

 often found above a quarter of a yard. 



The Scolopendra is otherwise called the 

 Centipes, from the number of its feet; and it 

 is very common in many parts of the world, 

 especially between the tropics. Those of the 

 East Indies, where they grow to the largest 

 size, are about six inches long, of a ruddy co- 

 lour, and as thick as a man's ringer : they con- 

 sist of many joints ; and from each joint is a 

 leg on each side : they are covered with hair, 

 and seem to have no eyes ; but there are two 

 feelers on the head, which they make use of 

 to find out the way they are to pass : the head 

 is very round, with two small sharp teeth, with 

 which they inflict wounds that are very pain- 

 ful and dangerous. A sailor that was bit by 

 one on board a ship, felt an excessive pain, and 

 his life was supposed to be in danger : how- 

 ever, he recovered by the application of three 

 roasted onions to the part, and was soon quite 

 well. Of this animal there are different 

 kinds ; some living, like worms, in holes in 

 the earth ; others under stones, and among 

 rotten wood ; so that nothing is more danger- 

 ous than removing those substances, in the 

 places where they breed. 1 



1 The Great Centipede. None of the insect tribe, the 

 scorpions excepted, are so formidable in appearance as 

 the centipede or great scolopendra. It is found in the 

 East and West Indies, and in various parts of Africa, in- 

 habiting chiefly the woods, where it is preyed upon by 

 the different species of snakes. It is, however, some- 

 times found in houses, and is said to be so common in 

 particular districts, that the inhabitants are obliged to 

 have the feet of their beds placed in vessels of water, in 

 order to prevent their being annoyed during night by 

 these horrible reptiles. 



The scolopendne vary greatly both in size and colour. 

 Some of them are of a deep reddish brown ; others of a 

 yellow ochre colour, livid yellow, or tinged with red ; and 

 are sometimes seen about a foot in length : they are, how- 

 ever, generally much less. Their legs terminate in very 

 sharp hooks, or nails, of a shining black colour; and all 

 the other legs are furnished with smaller ones of the same 

 kind. 



Gronovius says, that all the legs of this detestable ani- 

 mal are venomous ; but its most formidable weapons are 

 the two sharp and hooked instruments that are placed 

 under its mouth, with which it destroys its prey. At the 

 extremity of each of these there is a small opening, and 

 from thence extends a tube, through which it is supposed 

 the centipede emits the poisonous fluid into the wound 

 inflicted by these fangs. 



Leeuwenhock, desirous of ascertaining the influence of 

 the poison, placed a large fly within reach of a centipede. 

 He seized it between a pair of the middle feet, then passed 

 it from one pair to the next, till it was brought under the 

 fangs, which were plunged into its body, and it died in 

 stantly. St Pierre says, that in the Isle of France his 

 dog was bitten by one of them which was upwards of six 

 inches in length, and that the wound turned to a kind oi 

 ulcer, which was tliree weeks in healing. He was highly 



The G ally-worm differs from the scolopen- 

 dra, in having double the number of feet; 

 there being two on each side, to every joint of 

 the body. Some of them are smooth, and 

 others hairy; some are yellow, some black, 

 and some brown. They are found among de- 

 cayed trees, between the wood and the bark ; 

 as also among stones that are covered with 

 moss. They all, when touched, contract them- 

 selves, rolling themselves up like a ball. 

 Whatever may be their qualities in the tropi- 

 cal parts of the world, in Europe they are per- 

 fectly harmless ; having been often handled 

 and irritated, without any vindictive conse- 

 quences. 



All these, as well as the scorpion, are sup- 

 posed to be produced perfect from the parent, 

 or the egg ; and to undergo no changes after 

 their first exclusion. They are seen of all 

 and this is a sufficient inducement to 



sizes 



suppose, that, they preserve their first appear- 

 ance through the whole of their existence. It 

 is probable, however, that, like most of this 

 class, they often change their skins ; but of 

 this we have no certain information. 



CHAP. XL 



OF THE LEECH. 2 



THE last of this wingless tribe that I shall 

 mention is the Leech, which, like all the for- 



cliverted in observing one of them overcome by a vast 

 number of ants, that attacked it in conjunction, and, after 

 seizing it by all its legs, bore it along as workmen would 

 do a large piece of timber. Its poison is not more inju- 

 rious than that of the scorpion, and seldom proves fatal 

 to the larger animals. 



8 Cuvier classes leeches with worms, among the 

 Annelida, or invertebrated animals with red blood. 



The Medicinal Leech, (Hirudo medicinalis\ may be 

 known by having six yellowish lines, or striae, on its 

 back, while the under part is of a grayish hue, spotted 

 with black ; but, as we shall presently see, these mark- 

 ings are not uniformly found. The medicinal leech is 

 common throughout the whole of Europe, but is much 

 more abundant in the southern parts ; it is generally 

 about three inches in length. Formerly it was very 

 abundant in Great Britain, but the improvements in 

 agriculture, and the consequent drainage of the land, 

 together with the great use made of it in medicine, have 

 of late years rendered it of less frequent occurrence. 

 On this account great quantities of leeches are imported ; 

 these chiefly come from Bourdeaux and Lisbon. The 

 prevailing colour of the medicinal leech appears to vary 

 according to the nature of the soil on which it is found. 

 In winter the leech retires to waters of considerable 

 depth, and seeks shelter in the mud at the bottom ; but 

 in the summer it appears to delight in shallow pools, 

 basking, as it were, in the warmth of the sun: but if the 

 water it frequents is in danger of being dried up by the 

 summer heat, the leech buries itself in the mud at a 

 considerable depth. Just before a thunder-storm, leeches 

 appear much agitated, arid rise frequently to the surface 

 of the water; this, therefore, is considered by the leech- 



