328 On Plica Polonica. 
mode of life, or nearly the fame as in Poland— 
that its appearance affords evident relief to the 
fyftem, and its retroceffion is productive of dati- 
gerous confequences. ‘The idea that it is a real 
-and idiophatic difeafe, is confirmed alfo by its oc- 
currence in a variety of animals, and by the cir- 
cumftance of its being confined to particular parts 
of the head; for which no reafon can be affigned 
on the former fuppofition. 
A peculiarity of climate cannot be adduced as 
caufe of this difeafe. Poland differs little in this 
refpect from the adjoining countries. ‘The fummer 
heat is confiderable, the thermometer rifing fre- 
quently to 98°. 100°. 104°. and the cold in 
winter fo great, that it falls fometimes 10, 15 
degrees below 0, But though the changes in the 
atmofphere are fo remarkable, at different periods of 
the year, they take place with the utmoft regularity, 
the temperature paffing, by infenfible degrees, from 
one extreme to the other. 
The Poles themfelves are a vigorous, hardy race ; 
inured from infancy to labour, and to expofure to 
the viciffitudes of the atmofphere ; almoft regardlefs 
of cold, they frequently fleep in the open air. 
Their diet confifts chiefly of animal food, and they 
are much addiéted to the ufe of fpirits. They have 
an equal fondnefs for other ftrong ftimula- 
ting liquids. I have feen them drink, with the 
greateft pleafure, the falt brine in which herrings 
have 
