TV. AND REVIVED. 149 
wards faw that refufcitated wheel animals died at 
a much more gentle wisn of heat, when eer 
ed in the funfhine at 113°. 
The heat of the fire has the fame effect as that 
of the folar rays. Although the revived animals 
perifh at r11° and 113°, if dry, they do not 
lofe the power of refurrection at 144°. I could 
extend my experiments further with common fire 
than the fun. The heat was raifed above 144°, 
to fee whether dry wheel animals would revive ; 
for it was probable there were limits here, and 
thefe I found at 153°. Sand expofed to this 
heat, prefented few wheel animals ; and expofed 
to 158°, none appeared: But there is one cir- 
cumflance neceflary to be remarked: The ex- 
periments were made dry, that is, keeping the 
fand two or three minutes expofed to the heat. 
The confequences were very different on ufing 
wet fand, immerfing it two or three minutes in 
water warmed to that degree: then the animals 
did not revive after 131°. 
It is not difficult to explain why the deftruc- 
tion of regnimated wheel animals is eafier than 
when in their {tate of deficcation. The former 
are a kind of jelly, confequently moft delicate. 
Their minute filaments are eafily broken and de- 
ftroyed by the penetrating power of heat, which 
cannot operate with fuch facility when they are 
dry: then the parts are concentrated within 
K 3 themfelves, 
