210 THE ZOOLOGIST. 



their numbers. In cases where this has been properly carried 

 out, success has attended the experiments. Secondly, it should 

 be noted that slugs have the power of expelling a great quantity 

 of slime, which would naturally take up any poison in the form 

 of powder that may be laid down in their way ; and although 

 they have the power to crawl as it were out of this slimy 

 covering, and so leave the poison behind them, they cannot long 

 continue to supply this mucous matter, so that if two or more 

 dressings are applied soon after each other, the cuticle of the 

 slug may be reached. Dressings of salt and lime are by far the 

 most successful for destroying these pests, two or three dress- 

 ings being given, the second one some ten to fifteen minutes after 

 the first. Salt applied at the rate of four or five bushels per 

 acre, and lime at the rate of ten to twelve bushels per acre, will 

 clear any field of these noxious creatures, if done over twice in 

 succession, salt especially having an injurious effect on the 

 mucous membrane. It is useless, of course, to dress a field in 

 the hot part of the day, or in very dry weather. The dressings 

 should be applied when the slugs and snails are active, that is 

 after heavy rains, and in the evening and early morning, before 

 the sun is up; for as the sun rises the slugs, &c, disappear. 

 Slacked lime has no effect upon them. Snails are more difficult 

 to destroy, owing to their retracting their bodies into the shell 

 and closing the aperture ; and as they can live for several years 

 without food, they offer many difficulties in the methods of 

 destruction. Dressings of soot seem to be the most beneficial ; 

 the soot making the plant and ground obnoxious to the snails, 

 drives them from the land. Nitrate of soda is likewise a very 

 good dressing, both for slugs and snails, as well as for stimu- 

 lating plant-growth. Snails have many natural enemies in birds. 

 Thrushes and Blackbirds especially do much good in keeping them 

 in check. Ducks, Starlings, Rooks, and Pigeons also eat them 

 greedily ; as do also Moles, Shrews, and Toads. Several species 

 of mites are parasitic on slugs, but do not seem to affect them 

 injuriously. In gardens slugs and snails may be destroyed by 

 various traps : pieces of turnip and cabbage-leaves, spread upon 

 the ground, collected at night, will be found to have attracted 

 numbers from the surrounding soil ; they can then be easily 

 put into a pail of lime and so destroyed. But in the fields 

 the only practicable way of destroying them is by dressings, as 



