THE COMMON LEECH. 709 



when once laid in the ground sinks into its dust by natural corruption, untouched by 

 the imagined devourer. 



The so-called worms that feed upon decaying animal substances are the larvae of 

 various flies and beetles, which are hatched from eggs laid by the parent ; so that if 

 the maternal insect be excluded, there cannot be any possibility of the larvee. More- 

 over, neither the fly nor beetle could live at the depth 'in which a coffin is deposited in 

 the earth ; and if perchance one or two should happen to fall into the grave, they would 

 be dead in half an hour, from the deprivation of air and the weight of the superincum- 

 bent soil. 



Let, therefore, the poor Earth-worm be freed from causeless reproach ; and though 

 its form be not attractive, nor its touch agreeable, let it, at all events, be divested of 

 the terrors with which it has hitherto been clothed. 



The Earth-worm is a timid and retiring creature, living below the surface of the 

 ground, and having a great objection to heat and light. Heat dries up the coat of 

 mucus with which its body is covered and which enables it to slide through the ground 

 without retaining a particle of soil upon its surface. A very moderate amount of heat 

 soon kills an Earth-worm ; and if one of these annelids be placed in a spot where it 

 cannot hide itself from the sun's rays, it soon dies, and either melts into a kind of soft 

 jelly, or hardens into a thin strip of horny parchment. 



The vexed question of its use to agriculture is too wide a subject to be treated at 

 length in these pages ; but we may safely come to two conclusions first, that unless 

 it were of some use it would never have been made ; and secondly, that it will be wiser 

 to find out wherein its use lies than to kill it first and then perhaps discover that its 

 presence was absolutely needful and its absence injurious. 



The Earth-worm is of no direct use to mankind, except, perhaps, as bait for the 

 angler ; and for this purpose they are easily obtained by the simple process of driving a 

 garden-fork into the ground and shaking it about vigorously. The timid worms are 

 very much alarmed at the tremulous earth, and come to the surface for the purpose of 

 escaping, when they can be easily seized and captured. 



The COMMON LEECH is almost as familiar as the earth-worm, and is one of a genus 

 which furnishes the blood-sucking creatures which are so largely used in surgery. It 

 belongs to a large group of Annelida which have no projecting bristles to help them 

 onward and are therefore forced to proceed in a different manner. 



All these Leeches are wonderfully adapted for the purpose to which they are applied, 

 their mouths being supplied with sharp teeth to cut the vessels, and with a sucker-like 

 disk, so that the blood can be drawn from its natural channels ; while their digestive 

 organs are little more than a series of sacs in which an enormous quantity of blood 

 can be received and retained. 



Every one who has had practical experience of Leeches, whether personally a sufferer 

 or from seeing them applied to others, must have noticed the curious triangular wound 

 which is made by the teeth. If the mouth of a Leech be examined, it will be seen to 

 have three sets of minute and saw-like teeth, mounted on as many projections, which 

 are set in the form of a triangle. The wound made by this apparatus is rather painful 

 at the time, and is apt to be troublesome in healing, especially in the case of very thin- 

 skinned persons, requiring the application of strong pressure and even the use of some 

 powerful caustic. 



At one meal the Leech will imbibe so large a quantity of blood that it will need no 

 more food for a year, being able to digest by very slow degrees the enormous meal which 

 it has taken. It is a very remarkable fact, that the blood remains within the Leech 

 in a perfectly unchanged state as fresh, as red, and as liquid as when it was first 

 drawn and even after the lapse of many months is found to have undergone no 

 alteration. 



The very great difficulty in inducing a Leech to make a second meal is well known, 

 and can be well accounted for by the fact that it has already taken enough food to 

 support existence during one-sixth of its whole life. In England this is almost im- 

 possible, as the time occupied in reducing the Leech to the requisite state of hunger is 



