SLEEP. 



Clinque libidine femen profuderit. In fomniis id fit, certa 

 qiiidem sctatc, neque fere in fenis, perfacile in pueris. Sed 

 ■icque fenfatio, qm lomnii caufa ell, aut fola aut pura mcnti 

 reprtfentatur. Ex lege afTociationis idearum ad fimplicem 

 Uimiihim nafcitur idea femins pulchrx, amatx, quam am- 

 bias, quae cedat facilis : accedit leftulus, et omne fatellitium 

 arcaiii amoris. Et magis et magis poll pnmos fermones 

 adpropiiiquat comii)US fperata vokiptar, ut viciffim perinde 

 anxictatis hieroglypha continno graviora menti incum- 

 bunt." 



Tlie dreams which occur almoft nightly in moil indivi- 

 duals, (hew the aflivity of the internal mental operations 

 during fleep : voluntary motions are lefs commonly per- 

 formed. Some horfes fleep (landing ; and the lower jaw is 

 maintained elevated in us during fleep. The hand is often 

 raifed when any llimulus is applied to the body, although 

 it may not be llrong enough to interrupt fleep. The (atl of 

 children expelling their urine, when the pot is brought to 

 them, has been already noticed. Many perfons laugh, weep, 

 (Igh, and talk in their fleep : the words are indeed generally 

 indilliiidtly pronounced, and the fentences incomplete. 



The (leep-walkers diflFer from thefe only in degree. They 

 execute the voluntary motions, which arife out of the men- 

 tal procefles carried on in fleep. It would be endlcfs to 

 recount the particular cafes belonging to this fubjeft. It is 

 fufBcient to mention that individuals rife from bed aflcep, 

 and with their eyes clofed, and not only walk about the 

 room or houfe, going up or down (lairs, hnding their 

 way readily, and avoiding obftacles, but pafs fafely through 

 very dangerous pLces, as windows, or on the roofs of houies. 

 They execute, too. Hill more difficult feats. They drefs 

 themfelves, go out of doors, light a fire, undrefs and bathe, 

 iaddle and bridle a horfe, ride, write, make verfes, and exe- 

 cute all the aftions of life correftly, and even fometimes 

 acutely. During this time they are afleep ; the eyes are (hut, 

 or do not fee i( open ; the iris is not irritable. When 

 awakened, which is fometimes not eafily effeiited, they do not 

 remember what they have done. 



The proportion uf time paded in fleep differs in different 

 individuals, and at different ages. From fix to nine hours 

 may be reckoned about the average proportion. Men of 

 aftive minds, whole attention is engaged in a (eries of inte- 

 rellmg employments, fleep much lefs than tlie lilllefs and 

 indolent ; and tlie lame individual will fpend fewer hours in 

 this way, when (Irongly interefted in any purfuits, than when 

 the llream of life is gentle and undiilurbcd. Tlie great 

 Frederic of Pruflia, and John Hunter, who devoted every 

 moment of their time to the moll aftive employments of 

 body and mind, generally took only four or five hours fleep. 

 A rich and lazy citizen, whofe life is merely a chro- 

 nicle of breakfalis, dinners, (uppers, and fleep, will flum- 

 iier away ten or twelve hours daily. When any fubjeti 

 ilrongly occupies us, it keeps us awake in fpitc of our- 

 (elves. Thefe p'lenomena are confillent with what we have 

 already faid ; the animal organs, when the period of their 

 intermifljon and repofe has arrived, are kept in adtivity by 

 new and unufual caufes of excitation, and thus the ordi- 

 nary period of fleep may be pafTed over, and its ordinary 

 quantity much diminilhed. When a perfon, who has thus 

 been kept long awake by the occupation of his mind with 

 important aud urgent fubjedts, at lalt falls aflcej), the flighted 

 irritation calls up in the fancy all the trains of tliouglit 

 which have jull occupied u', and fets at work again all the 

 internal machinery winch has hardly yet become quiet ; the 

 fleep, under fucli circumllances, is imperfeiit, and mueli dil- 

 turbed by dreaming. 



The newly-born child fleeps mod of its time ; it feems to 

 Vol. XXXIII. 



wake merely for the purpofe of feeding. Some have called 

 (octal exifttnce a perpetual fleep ; but the animal organ?, 

 never having been yet exercifed, can hardly be faid to be 

 in a Hate of repofe. See Embuvo. 



For the firll two or three yearf, children (leep more than 

 once in the twenty-four hours. Again ; very old perfons 

 fleep much of their time : in the natural progrefs towards 

 death, the animal faculties are firft extinguilhed ; accord- 

 ingly, when they begin to decline in decrepid old age, the 

 periods of their intermilTion are longer. The celebrated 

 De Moivre, when eighty-three years old, was awake only 

 four hours out of the twenty-four (Hid. de I'Acad. des 

 Sc. for 1754) ; and Thomas Parr at lalt flept the gieateft 

 part of his time. Aniin.ils which do not prey by night, 

 feem to pafs as much time afleep as awake ; that is, they 

 fleep during the dark, and are awake fo long as the fun is 

 above the horizon. 



The (late of torpidity in which many animals pafs the 

 winter months, cannot properly be called ilcep ; it is not 

 a repofe of the animal organs, confequent on the fatigue 

 produced by their exercife ; but is a peculiar condition of 

 the whole frame, affefting the internal ai well as the external 

 organs, and caufed diredtly by the aflion of cold. 



The exhauftion of the powers of the animal organs bv 

 exercife being the determining caufe of fleep, it comes on 

 after the clofe of our daily occupations, when darknefs ne- 

 cedarily caufes an intermilTion of labour and a general quiet, 

 which are favourable to repofe. The number of hours de- 

 voted to aftive occupation, and the time at which difpofition 

 to fleep is felt, are indiienced confiderably by habit : after 

 confiderable and unufual exertion, fleepinefs will be felt in 

 the day-time. 



The period of fleep may be protraftcd, by unufual exci- 

 tation, much beyond the ordinary period ; but the effeft 

 is lod after a certain time, and fleep comes on under circum- 

 ftances, which appear at firll moll unfavourable to it. An 

 eye-witnefs reported that lomc boys, completely exhauded 

 by exertion, fell afleep amid all the tumult of the battle of the 

 Nile ; and other inltances are known of (oldiers fleeping amid 

 difcharges of artillery, and all the tumult of war. , Couriers 

 are known to fleep on horfeback, and ooachmen on their 

 coaches. A gentleman who faw the faft, reported to the 

 writer of this article, that many (oldiers in the retreat of fir 

 •lohn Moore, fell aflcep on the march, and continued walking 

 on. Even (Iripes and tortures cannot keep off fleep be- 

 yond a certain time ; but it then indicates the greatell ex- 

 haudion, and confequently affords an unfavourable progiiofis. 

 Noifes at firft prevent us from deeping, but their influence 

 foon ceafes, and perfons red foundly in the moll noify fitua- 

 tions. The proprietor of fome vail iron-works, who flept 

 clofe to tliem, through the incedant din of hammers, forges, 

 and blad-fiirnaccs, would awake if there was any interrup- 

 tion during the night. And a miller, being very ill and 

 unable to fleep, when his mill was flopped on this account, 

 reded well and recovered quickly when the mill was fct a, 

 going again. 



Great hunger prevents fleep ; and cold affefting a part of 

 the body has the fame effeft. Thefe caufes operated on the 

 unfortunate women who lived thirty-four days in a fmall 

 room overwhelmed by fnow, and with the flighted fufte- 

 iiance : they hardly flept the whole time. ( SoinisRagiona- 

 mento fo[)ra un (alto avvenuto in Bergemoletto, See. p. 74.) 

 Indigellion, and various bodily afleftions, produce fleeplefl- 

 nc(p. We have .ilready noticed, that all mental occupa- 

 tions attended with intenfe tliought, and great intercd, 

 prevent fleep ; and any great aft'eftions of the mmd have the 

 fame cdeft. 



S It 



