50 CLASS MOLLUSCA. 



produced by them are very considerable; they are par- 

 ticularly destructive in orchards and kitchen-gardens. 

 On this account, many methods have been recommended 

 for the purpose of destroying them. Although many 

 of these are tolerably successful, there is no plan more 

 likely to keep the breed of Snails under, particularly in 

 enclosed gardens, than that of early rising and gathering 

 them, if we may so express ourselves, while the dew is 

 yet on the grass : if the shells are then broken, they 

 become excellent food for poultry. Ducks may some- 

 times be allowed to wander in the garden, as they do 

 but little damage to the vegetation, and are great 

 destroyers both of Snails and slugs. 



A singular account of the instinct of Snails is, per- 

 haps, worth recording. 



The garden of a small house, by the side of one of 

 the roads leading into London, was much infested by a 

 colony of Snails; the proprietor of this house, desirous 

 of getting rid of the pest, and yet unwilling to kill the 

 Snails, collected them, and threw them unharmed into 

 the road; but still, he every morning discovered as many 

 Snails among his pinks and tulips as he had removed 

 the previous day ; this somewhat puzzled him, until once, 

 on leaving his house early, he perceived the Snails 

 which he had but an hour before thrown into the dusty 

 road, moving, not in a body, but each from the spot on 

 which it was thrown, in a direct line from that spot to 

 the low wall which encompassed the garden, as if they 

 comprehended the mathematical fact that, " a straight 

 line is the nearest way from one given point to another." 

 How were these Snails aware that by moving in that 

 direction, they should arrive at a green spot? From the 

 road nothing could be visible to them but dust, — from. 



