WORMS. 283 



around the mouth, which is armed with jaws, and a larger one at the tail ; they are 

 generally dark colored, very much mottled, often having fine lines and dots of bright 

 hues ; they are properly aquatic, and occur in both fresh and salt water. 



There are three families, of the first of which, the Gnathobdellid^, the medical 

 leech, Ilirudo medicinalis, is typical. The variety known as officinalis, nieasures, 

 when at rest, some three or four inches. The color of the species is greenish or 

 olive green, with six rust-red, thread-like longitudinal bands, speckled with black; 

 ventral surface, greenish yellow, spotted with black. The mouth has three radiating 

 jaws, with saw-like edges; when the animals bite through the skin, the wound 

 made consists of three cuts radiating from a common centre, ieach jaw making 

 a separate slit. The head is furnished with ten eyes and other special sense organs. 

 The natural habitat of the common leech is in swamps and brooks where the water 

 flows slowly ; stagnant pools are unsuited to it ; it preys on all vertebrates, both 

 fishes and amphibia, and on mammals which come to the water to drink or bathe. 

 It fastens itself upon its victim by means of its suckers, then cuts the skin, fastens 

 its oral sucker over the wound, and pumps away until it has completely gorged 

 itself with blood, distending enormously its elastic body, when it loosens its hold 

 and drops off. Its attacks cause very little pain ; boys in bathing are often feasted 

 upon without being awai-e of it until they see the dark foe against the light skin. 

 It is this power of extracting blood almost painlessly which has induced physi- 

 cians to put them in requisition. They are generally kept by apothecaries, and sup- 

 plying the market has become a considerable industry in westei-n France. In that 

 country it is said that they have leech plantations, swampy territories, which are care- 

 fully freed from all animals that might destroy the leeches, such as large frogs and 

 certain fishes. To nourish them, worn out horses and cattle are purchased and driven 

 into the leech enclosures, in which they are left to perish, death coming soon from loss 

 of blood, and preceded by probably very little pain. The custom is not so humane as 

 one would be glad to demand, but, on the other hand, there is no reason to sii])iiose 

 that it inflicts great suffering on the horses, etc. The leeches are collected in the fall, 

 and, to a less extent, in the spring; for if gathered in summer they do not bear trans- 

 portation well. In autumn, however, they are in the best condition, and, if captured 

 then, will survive months without food if properly cared for. The animal casts its 

 skin very frequently, and requires something to rub and scrajie against, to remove the 

 old slough, hence they must be supplied with plants and soil through which to crawl, 

 as well as water. They move about either by crawling with the aid of their suckers 

 somewhat in the fashion of an inch-worm, or else by swimming, at which they are 

 adepts, but they evidently prefer to have a firm hold. Sometimes they plant them- 

 selves by the posterior sucker, and, stretching out their body, throw it into undulations, 

 which pass from the head backward, and are sustained, an uninterrupted succession of 

 waves, for long periods. When reposing, they assume all sorts of attitudes, to look at 

 some of which makes one's back ache. The common way to catch them is for a man 

 to stand in the water with bare feet and legs, then stir up the mud around him and 

 pluck off those leeches which fasten upon him ; some of these collectors become quite 

 bloodless and sickly. ' Other modes of capture have been tried, but the belief that 

 leeches must be captured upon the human skin still prevails, and leech culture there- 

 fore still goes on according to the ancient and semi-barbaric rules. 



The eggs are laid in the ground; in the spring the leeches burrow into the moist 

 earth, a little above the water level. Towards the end of June they form their co- 



