60 MR. NEWPOBT ON THE NATURAL HISTORY 



kill a small suail, of about the size of a large pea, in less than 

 two liovirs. 



That two or three bites are usually required to kill a snail about 

 the size of a small bullet. 



That the effect produced by the bite is not that of mere mechf^- 

 nical iiijury. Nor does it appear that a bite at one spot is more 

 fatal than at another ; for although the larva usually attacks the 

 head of the snail, it wounds it in other parts also with similar 

 results. But if the snail is very large, instinct prompts the glow- 

 worm to bite it two or three times at the foot, before venturing to 

 strike it on the head. 



That even when the snail is twice pierced through its head with 

 a needle near the cerebral ganglion, or through its body, but little 

 effect is produced, though when this same snail Avas bitten by the 

 larva it was dead in two hours. 



That when two small snails about the size of grapes were em- 

 ployed, one being pierced through and through with a needle, and 

 the other not so injured, but bitten once ouly by a large larva, both 

 snails immediately retired into their shells ; and that whilst the 

 bitten one never came forth again and was nearly dead at the end 

 of two hours, the other snail was alive and apparently well on the 

 followiug day. 



I noticed also that, although a snail may be bitten once by a 

 small larva and not appear at the time to have been much injured, 

 yet it frequently dies after some houi'S. Tliis fact still further tends 

 to support the \dew that some poison is injected, or some sei'ious 

 derangement of the vitality of the snail is occasioned at the time of 

 inflicting the wound, and to confirm it in a negative way by the 

 fact, that if tlie larva be allowed to exhaust its force, of whatever 

 nature this may be, by repeatedly biting a snail, and then be em- 

 ployed to wound a very much less snail, the effect it produces is 

 far less marked than if it had not previously bitten any. 



What is the nature of this influence ? Can it at all resemble 

 that of the shock of the electric eel or of the torpedo, both of 

 which we know become exhausted by the repeated use of their 

 power ; or can it resemble that of the ray or stinging skate, which 

 is believed to inject a poison with its sting ? 



But although the effect is fatal to a small snail, even wdien the 

 larva has previously exhausted its force, it is yet exceedingly 

 slieht in the latter case, when the creature is allowed to strike a 

 large snail. On one occasion I employed a full-grown larva which 

 had been used before, to attack a full-grown Helix that was as 



