98 CORRESPONDENCE OF RAY. 



wardly. A fourth, to try, if occasion serveth, the virtue 

 of Lichen cinereus terrestris [Pdtidea canina, Ach.], 

 which was said to be exceedingly efficacious in curing 

 dogs bitten by mad dogs. A fifth, to inquire of Mr. Pisher 

 whether he be master of the experiment of dissolving 

 glass, and reducing it into a white calx ; and after the 

 glass is well moistened with the menstruum, whether it be 

 capable to be shaved with a knife, almost like horn? 

 And, farther, whether the menstruum employed for that 

 purpose performs upon all sorts of glass ? 



1 intreat you, sir, to present Mr. Ray with my hearty 

 service ; and, he being concerned in some of these par- 

 ticulars, to give him the reading of this paper. 



Dr. Grew is now amongst us at Arundel House, making 

 now and then very good observations upon plants ; and 

 having showed to the company, among divers particulars, 

 the tracheae mentioned by Malpighi in his ' Discourse of 

 Vegetables,' that you have seen. 



He hath been desired to endeavour whether he can 

 discover any such thing as a peristaltic motion in plants 

 when growing ; for which purpose he hath been directed 

 to choose some of the bigger sort, Avherein that motion, 

 if there be any such, is like to be more discernible. 



We hope, sir, that you and your friend will join in 

 making a research so considerable. 



I presume you know that Mr. Boyles's essay of the 

 ' Origin and Virtues of Gems ' is now abroad ; and I be- 

 lieve that Signer Malpighi's discourse ' De Formatione 

 PuUiin Ovo Fcecundo,tamnon Incubato quamlncubato' 

 will be printed in a short time, I desire very much to 

 know that these lines are come to hand.* 



Loudon, July 6, 1672. 



* [To whom tliis letter was addressed does not appear ; probably Mr. 

 Willughby.] 



