1108 PRACTICE OF AGRICULTURE. Part III. 



7616. The craiv or crayfish (Cancer ^'tstacus L.,fig. 962.), called (sometimes the fresh 

 962 water lobster, inhabits still rivers, and forms 



holes in the banks. 



7617. They are said to be nutritious and of an 

 excellent flavour, and are prepared in cooking like 

 lobsters or shrimps. In former times they were 

 celebrated for sundry medicinal virtues, but these 

 seem to be now forgotten. The flavour of these ani- 

 mals, nevertheless, depends entirely on the nature 

 of their food. Like all others of their tribe, they feed 

 principally upon flesh. They might be advantageously 

 cultivated in ponds and marshes, but should not be 

 put into fish ponds, as they are detrimental to the 

 fry. A breeding stock may frequently be purchased 

 in Covent Garden market, or procured from any of 

 the small rivers near London ; they are also said to 

 be plentiful near Alnwick in Northumberland. 



7618. The edible snail (Helix pomatia L., fig. 71. a), although a native of the Con- 

 tinent, has been long naturalised in some parts of England. 



7619. It is the largest species found in Europe. The animal being fleshy, and not of an unpleasant 

 flavour, has been used as food from early times. It owes its introduction into England to certain medicinal 

 virtues, no less than to its repute on the Continent as an article of food ; but the first of these properties 

 has long since been forgotten, and no progress has yet been made in introducing it on our tables. It is 

 not so abundant in Italy as the common garden snail (H. hort^nsis L.), which may be seen, exposed in 

 cages, in the markets of Genoa and other cities. "We have no certain information which of these species 

 was held in repute among the Romans, who had their cochlearia or stews, where snails were bred, and 

 fattened upon bran and sodden lees of wine. The H. pomatia is preserved near Vienna in large pits, 

 covered with boards, and fed with cabbage leaves and other vegetables. 



7620. The medicinal leech (^Tiriido medicinalis X.) grow^s to the length of two or 

 three inches. Tlie body is of a blackish-brown colour, marked on the back with six 

 yellow spots, and edged with a yellow line on each side ; but both the spots and the lines 

 grow faint, and almost disappear at some seasons. The head is smaller tlian the tail, 

 which fixes itself very firmly on any thing the creature pleases. It is viviparous, and pro- 

 duces but one young at a time, which is in the month of July. It is an inhabitant of 

 clear running water ; but in winter the leech resorts to deep water, and in severe weather 

 retires to a great depth in the ground, leaving a small aperture to its subterranean habit- 

 ation. It begins to make its appearance in March or April. "Water alone is not the 

 natural element of leeches, as it is supposed, but conjointly with ground or mud. 



7621. The usual food of the medicinal and trout leech is derived from the suction of the spawn of fish ; 

 and leeches will not unfrequently be found adhering to the fish themselves : but frogs form the most con- 

 siderable portion of their food ; hence, the best leeches are found in waters much inhabited by these 

 animals. The medicinal and trout leech do not, like the horse leech, take any solid food ; nor have they 

 the like propensity to destroy their own or any other species of the genus ; but these the horse-leech will 

 not hesitate to devour. {Newton's Journal, vol iv. p. 313.) If put into shallow clear ponds it will breed 

 freely, and this is practised by some herbalists and apothecaries in the neighbourhood of London. 



7622. The use of leeches for the purpose of local bleeding is very considerable. There are four principal 

 importers of leeches in London alone, whose average imports are said to be 150,000 per month each ; 

 making a total of 600,000, or seven millions two hundred thousand in one year. On the Continent, where 

 they are obtained at a much cheaper rate, the numbers employed are enormous. {Ibid.) The London 

 market is partly supplied from the lakes of Cumberland, where the leeches are caught by women, who go 

 into the water bare-legged, and after a few have fastened^ they walk out and pick them ofE A good many 

 are also brought from Holland. 



Chap. XII. 



Animals noxious to Agriculture. 



7623. Almost evert/ animal may he injurious to the agriculturist in some way or other. 

 All the cultivated live stock will, if not excluded by fences, or prevented by herding, eat 

 or tread down corn crops or other plants in culture. Those animals, as the dog and 

 ferret, which assist him in deterring or in catching noxious animals which would prey on 

 others, will tliemselves become depredators if not attended to ; and even man, the only 

 rational, and therefore the most valuable of agricultural servants, will prove, under certain 

 circumstances, the greatest of all enemies to the agriculturist. We shall glance at the 

 different animals more especially noxious in the order of their usvial classification. 



Sect. I. Noxious Mammalia. 



7624. Of noxious Mammalia man, in a demoralised state, is the most injurious. The 

 remedy is furnished by the law ; the preventive is good education, and civil and kind 

 treatment by the master. 



7625. The fox (Clinis Fulpes) commits great ravages among Iambs, poultry, geese, &-c. To destroy it, 

 the farmer must take a sheep's paunch and fasten it to a long stick; then rub his shoes well upon the 

 t>aunch, that the fox may not scent his feet. He should then draw his paunch after him as a trail, a mile 



