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* I/; 
without any obvious caufe, they become 
uneafy and reftlefs, petulant and quarrel- 
fome, and are feized with paroxyfms of 
anger and rage. This tumult fubfides 
by degrees, and they referve their tran¬ 
quility. Thus, after the horrors of the 
temped:, the air becomes calm, and the 
fky recovers its ferenity. 
Is it poffible in this way to account for 
the periodical return of difeafes ? 
There is not any inftant in life in which 
the brain ceafes to be in action; confe- 
quently the eledricity by which it ads, 
ought to exift conftantly in it in dif-equi- 
librium. (Sbilancio.) I fuppofe that it 
lilcewife exifts in the fame way in the fpi- 
jnal marrow and nerves, with this differ¬ 
ence, that in fome of the nerves it is not 
excited, except under certain circumftances. 
Without dwelling upon this theory, I Hi all 
con te.nt.my felf with obferving, that the brain, 
Ipingl marrow, and nerves have a fpecific 
R conftitu- 
