360 NATURAL THEOLOGY. 



I. The shells of snails are a wonderful, a me- 

 chanical, and, if one might so speak concerning 

 the works of nature, an original contrivance. 

 Other animals have their proper retreats, iheir 

 hybernacula also, or winter-quarters, but the snail 

 carries these about with him. He travels with 

 his tent ; and this tent, though as was necessary, 

 both light and thin, is completely impervious 

 either to moisture or air. The young snail comes 

 out of its egg with the shell upon its back ; and 

 the gradual enlargement which the shell receives 

 is derived from the slime excreted by the animal's 

 skin. Now the aptness of this excretion to the 

 purpose, its property of hardening into a shell, 

 and the action, whatever it be, of the animal, 

 whereby it avails itself of its gift, and of the con- 

 stitution of its glands, (to say nothing of the work 

 being commenced before the animal is born,) are 

 things which can, with no probability, be referred 

 to any other cause than to express design; and 

 that not on the part of the animal alone, hi which 

 design, though it might build the house, it could 

 not have supplied the material. The will of the 

 animal could not determine the quality of the ex- 

 cretion. Add to which, that the shell of the 



it to different bodies, move from one to the other. The observa- 

 tions more accurately made of late years, show that this power is 

 not possessed by the animal, but that it requires the aid of a cur- 

 rent of air to direct the thread. This correction, however, of the 

 former opinion, in no way weakens the force of the argument in 

 the text. 



