[ *22 ] 
of adtual vegetation, or even in fuch a 
ftate as to be capable of vegetating under 
certain circum fiances, in lift be deprived of 
their principle of vegetation before they can 
be frozen. Vegetables have a power within 
themfelves of producing or generating 
heat, but not alw'ays in proportion to the 
diminution of heat by the application of 
cold, fo as to retain at all times an uni¬ 
form degree of heat; for the internal tem¬ 
perature of vegetables is fufceptible of 
variations to a much greater extent indeed, 
than that of the moft imperfedt animals, 
but ftill within certain limits. Beyond 
thefe limits, the principle of vegetable, as 
of animal life, refills any further change. 
The heat of vegetables varies according to 
the temperature of the medium in which 
they are, which we difeover by varying 
that temperature, and obferving the heat 
of the vegetable. The expence of the 
vegetating powers in this cafe, is propor¬ 
tioned 
