100 Gaspard's Memoir, S^c. 



§ 17. It appears from the experiments of M. Gaspard, that the 

 return of warmth is not alone sufficient to restore the animation of 

 these animals. If they were exposed during the winter to a dry 

 heat of from 60" to 100" for several days, or even weeks, not one 

 made its appearance. Whilst on the contrary, those which were 

 placed in a deep recess, the regular temperature of which was 50*, 

 eame forth in April or at the beginning of May without any en- 

 crease of temperature. But such as were placed in water and ex- 

 posed to 77° in two or three days broke their operculum and came 

 forth ; this experiment was equally successful when made in Ja- 

 nuary or April, and when the temperature was at 60° or 75°. And 

 it is found that exposure to damp is so necessary to their re-ani- 

 mation, that if two be placed near each other in rainy weather, 

 and one of them be covered with a glass, it remains without an 

 effort to emerge from its confinement long after the other has 

 broken its operculum and resumed its functions. It appears there- 

 fore from these facts that the return of the spring, with heat and 

 moisture, all combine to effect their re-animation. 



§ 18. The author proceeds to state the circumstances by which 

 the resuscitation may be retarded ; and he found that this could 

 be effected with the greatest certainty by exposing them constantly 

 to a dry heat, by which he kept some of them from Bursting their 

 operculum, even till October. And these invariably became re- 

 animated on being placed in water, though they were very feeble 

 and ultimately perished. Although the author preserved them in 

 this state for even 12 months, he does not consider the state of 

 actual torpidity to continue beyond the usual period of hibernation, 

 but that the heart and other organs re-commence to a certain de- 

 gree their functions, which accounts for their being always found 

 so enfeebled afterwards. 



^19. These circumstances lead to the consideration of the fact 

 that the snails retire within their shells during the heat of summer ; 

 closing the aperture with a membrane. In this state they remain 

 night and day whilst the dry heat continues, but no sooner does a 

 shower fall than they break the covering and walk ; and this may 

 be at any time effected by watering the ground near them. 

 [To be continued.] 



