438 ESSAYS anp OBSERVATIONS 
I. WHEN one has eat or drunk a great deal 
before fleep, his pulfe will be, not flow, but 
quick and full; becaufethe ftimulating power 
of the blood is increafed, by a large quantity 
of chyle received into it. Much the fame 
thing may happen from fleeping in too hot 
an air, or under too great a weight of cloaths: 
for we know, that heat quickens the circu- 
lation of the fluids in all animals. On 
the other hand, when one has fafted long 
before fleep, and lies very cool, his pulfe 
will, in time of it, be unufually flow. 
But when the blood is neither loaded 
with new chyle, nor altogether deftitute of 
it; neither too much heated by cloaths or 
the external air, nor toocool, thro’ want of 
proper covering ; its ftimulating quality will 
neither be augmented nor diminifhed by 
fleep; but will continue the fame as in a per- 
fon who is awake in the fame circumftances. 
It remains therefore, that the flownefs of the 
heart’s motion in time of fleep, be owing, 
either to the flower return of the venous 
blood to it, or to fome diminution of its fen- 
fibility. 
Il. Every one knows, that the affections 
of the mind difturb the motion of the heart; 
that 
