SECT. XVIIL 14. O F S L E E P. 



tions, we begin to awake ; the larger mufcles of the 

 body are brought into action to remove that irrita- 

 tion or fenfation, which a continued pofture has 

 cauied ; we itretch our limbs, and yawn, and our 

 fleep is thus broken by the accumulation of volun- 

 tary power. 



Sometimes it happens, that the act of waking is 

 fuddenly produced, and this foon after the com- 

 mencement of fleep ; which is occafioned by fome 

 fenfation fo difagreeable, as inltantaneoufly to excite 

 the power of volition ; and a temporary action of 

 all the voluntary motions fuddenly fucceeds, and we 

 ftart awake. This is fometimes accompanied with 

 loud noife in the ears, and with fome degree of fear ; 

 and when it is in great excefs, fo as to produce con- 

 tinued convulfive motions of thofe mufcles, which 

 are generally fubfervient to volition, it becomes 

 epilepfy : the fifs of which in fome patients gene- 

 rally commence during fleep. This differs from the 

 night-mare defcribed in No. 3. of this Section, be- 

 caufe in that the difagreeable fenfation is not fo 

 great as to excite the power of volition into action ; 

 for as foon as that happens, the difcafe ceafes. 



Another circumitance, which fometimes awakes 

 people foon after the commencement of their fleep, 

 is where the voluntary power is already fo great in 

 quantity as almoit to prevent them from falling 

 afleep, and then a little accumulation of it foon again 

 awakens them ; this happens in cafes of infanity, or 

 where the mind has been lately much agitated by 

 fear or anger. There is another circumftance in 

 which fleep is likewife of (hort duration, which arifes 

 from great debility, as after great over-fatigue, and 

 in fome fevers, where the itrength of the patient 

 is greatly diminifhed, as in thefe cafes the pulfe 

 intermits or flutters, and the refpiration is pre- 

 vioufly affected, it feems to originate from the want 



of 



