THE EARTH. 345 



;al liouis together? I must faiily confess my ignorance; al- 

 though It is easy to tell what philosophers say upon the subject. 

 Sleep, says one of them, ' consists in a scarcity of spirits, by 

 which the orifices or pores of the nerves in the brain, through 

 which the spirits used to flow into the nerves, being no longer 

 kept open by the frequency of the spirits, shut of themselves ; 

 thus the nerves, wanting a new supply of spirits, become 

 lax, and unfit to convey any impression to the brain. All 

 this, however, is explaining a very great obscurity by some- 

 what more obcsure ; leaving, therefore, tho&e spirits to open 

 and shut the entrances to the brain, let us be contented 

 with simply enumerating the effects of sleep upon the human 

 constitution. 



In sleep, the whole nervous frame is relaxed, while the heart 

 and the lungs seem more forcibly exerted. This fuller circulation 

 produces also a swelling of the muscles, as they always find who 

 sleep with ligatures on any part of their body. This increased 

 circulation also, may be considered as a kind of exercise, which 

 is continued through the frame ; and by this, the perspiration 

 becomes more copious, although the appetite for food is entirely 

 taken away. Too much sleep dulls the apprehension, weakens 

 the memory, and unfits the body for labour. On the contrary, 

 sleep too much abridged, emaciates the frame, produces melan- 

 choly, and consumes the constitution. It requires some care, 

 therefore, to regulate the quantity of sleep, and just to take as 

 much as will completely restore nature, without oppressing it. 

 The poor, as Otway says, sleep little ; forced by their situation, 

 to lengthen out their labour to their necessities, they have but a 

 short interval for this pleasing refreshment ; and I have ever been 

 of opinion, that bodily labour demands a less quantity of sleep 

 than mental. Labourers and artizans are generally satisfied with 

 about seven hours ; but I have known some scholars who usual- 

 ly slept nine, and perceived their faculties no way impaired by 

 oversleeping. 



The iamous Philip Barrettiere, who was considered as a pro- 

 digy of learning at the age of fourteen, was known to sleep regu- 

 larly twelve hours in the twenty-four ; the extreme activity 

 of his mind, when awake, in some measure called for an ade- 



I Ku)iauit. 



