infests the Lombard y- Poplar. 15 i 



the hairs in their bodies had the quality of a nettle, and 

 gave them a more acute, though less durable pain." Vol. 

 3, p. 520. Does the hair chiefly serve to break through 

 the insensible epidermis, making access, for the subtil 

 poison, to the organs endued with sensibility ? If the 

 hand were pricked a thousand times, with a very fine 

 lancet, would the singular burning sensation arising from 

 nettles be the consequence ? Or would it continue four 

 or five days ? Let gentlemen decide for themselves. 



Dr. Goldsmith, writing on a particular species of the 

 Caterpillar, says, " and generally if handled it stings 

 like nettles. Some of them even cause this stinging pain 

 if but approached too nearly." Vol. 4, p. 207. Then it 

 appears from this learned and cautious Naturalist, of 

 great capacity of observation, and equal ability and inte- 

 grity in detailing what he had observed, that a certain 

 species does produce stinging pain without being 

 touched : by means of an apparatus, no doubt, fitted 

 by nature for the defence of the animal, or the means of 

 taking its prey. Is this mechanical ? even if the sting 

 of the nettle be, which, I believe, few prudent Medical 

 Philosophers would undertake to prove. Is it defensi- 

 sible from this, that in all ages, and by every writer 

 " since the capacity of man to observe," that " the Cater- 

 pillar in all its varieties has been considered as innocent," 

 or because it ends in a butterfly it must be harmless ? 



Of the particular manner in which animals may play 

 off their batteries of mischief to our annoyance, and their 

 own advantage, we, in many instances, must be content to 

 be ignorant. We advance from the cause to the effect, 



