VOL. XXII.] PHILOSOPHICAL TRANSACTIONS. 503 



parent, and of a tough and viscous nature, whence I thought whether this 

 might not be the substance of which the threads were formed, and also whether 

 the body of the spider was not so framed, as to be able to press or insinuate 

 into its working instruments, that matter, which is the foundation of the threads 

 issuing from thence. I have often cut off a piece of that part of the spider's 

 body from whence these threads proceed, and afterwards drawn long threads 

 out of it. 



I once took a very small frog, the length of whose body was about an inch 

 and a half, and put him into a glass tube, together with a large spider, in order 

 to see how they would behave ; when I observed that the spider passed by the 

 frog without touching him, but yet he had drawn out his stings, as if he in- 

 tended to have fallen directly upon the frog. Afterwards I caused the frog to 

 run against the spider, who thereupon struck it in the back with its stings, and 

 wounded the frog in two several places, in such a manner, that in one place he 

 left a red speck, and in the other a blue one. Hereupon I brought them to- 

 gether again, when the spider struck his stings into the fore-leg of the frog, 

 who upon that struggled so hard that the spider was forced to leave him, and I 

 observed that some few of the blood-vessels in the frog's legs were wounded. 

 Once again I forced the frog to jostle the spider, who upon that struck both 

 his stings into the frog's nose, after which they both stood still about half a 

 minute, then opening the glass I took the spider out, while the frog sat still 

 about an hour, then stretched out his hinder legs, and died. 



The next day I took another frog, about the same size with the former, and 

 another spider, and putting them both into the same glass, the spider passed 

 by the frog without meddling with it ; but when I suddenly shook them to- 

 gether, the spider struck both his stings in the frog's back, but I could not 

 perceive that he was wounded so far as the veins, as there was no^blood spilt. 

 This frog was very shy of the spider, and as soon as the spider came near him, 

 or touched him with his feet or claws, the frog used his utmost efforts to avoid 

 him. Again, I brought the frog so near as to touch the spider with the fore- 

 part of his body, who thereupon gave him two blows with his stings in the 

 lower part of the head, one of which pierced the blood-vessels, so that there 

 remained a red spot ; the spider presently quitted the frog, because of the strong 

 efforts he made to get from it, and then set itself to cleanse its stings with a 

 moisture that came from its mouth for that purpose. I then separated the 

 spider from the frog, and viewed the circulation of the blood in the veins of 

 the latter, that I might see whether any alteration was occasioned by the wound 

 received from the spider ; but I could discover nothing, neither could I perceive 

 that the frog had received any harm, for the next day he was as brisk as ever. 

 VOL. IV. 4 G 



