FRANCIS WILLUGHBY. 
85 
asserted, that the main body of the sap being not 
returned to the point whence it was propelled, 
like the blood to the heart in animals, the term 
circulation of the sap, in the sense of its passing 
round in the same track, its motion constantly 
tending to the same point from whence it began, 
is not proved to be appropriate.* Mr Willughby 
also communicated many other papers during the 
same year, containing observations which he 
himself made on the black poplar, the dwarf 
oak, &c. 
In the month of July, 1670, Dr Edmund King 
had communicated to the Royal Society some ob- 
servations he had made on certain insects lodging 
themselves in old willows, curiously wrapt up in 
green leaves, in channels or burrows, each with 
twelve, fourteen, or sixteen leaves around the 
body, and several of them having as many little 
round bits of leaves at each end to stop them up 
close ; which, thus made up, were near an inch 
long, put in one after another into a bore made 
in the wood fit for their reception, “ resembling 
eartrages in powder wherewith pistols are wont 
to be charged, or like long slugs of lead ; some 
placed so near as to touch, and others at a con- 
siderable distance, in burrows like- those of 
rabbits.” 
The following are extracts from two letters by 
Mr Willughby to the publisher, from Astrop, 
- August 19, and from Middleton, September 2, 
■* Rees’s Cyclopaedia ; article, Circulation of the Sap. 
