WORMS. 



l-i2 



around tlio 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 j)ropei'ly aquatic, and occur in both fiesh and salt water. 



There are three families, of the first of which, the Gnathoudellidji:, the medical 

 leech, Ilirudo inedicinalis, is typical. The variety linown as officinalis, measures, 

 wlien at rest, some three or four inches. The color of tlie species is areenish or 

 olive green, with six rust-i-ed, 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, each 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 

 Hows slowly ; stagnant pools are unsuited to it ; it prej-s 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 tlie wound, and pumps away until it has completely gorged 

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

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

 ujion without beu)g aware of it until they see the dark foe against the light skin. 

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

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

 plying the market has become a considerable industry in western France. In that 

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

 fully freed from all animals that might destroy the leeches, such as large fi-ogs 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 ])erish, death coming soon from loss 

 of blood, and preceded by ju'obably 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 sn]>pose 

 that it inflicts great suffering on the horses, etc. The leeches arc 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 req\iires something to rub and scra])e against, to remove the 

 old slough, hence they must be supjilied with ])lants 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 tliey are 

 adepts, but they evidently prefer to have a firm hold. Sometimes they \AM\t theni- 

 sehes by the posterior sucker, and, stretching out their bod}-, throw it into undulations, 

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

 waves, for long periods. When reposing, they assume all sorts of attitudes, to lot)k 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 

 jiluck off those leeches which fasten u])on him; some of these collectors become quite 

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

 leeches must lie 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- 



