6'. : ' ^. C>r ]ar abiliTy 



to^e^..- . - - v.m the dry -• . ; . ..„ . . ..>.-: ..... action of 

 the lowest teinp»era tares when dried, the tardi grades 

 deserve to be mentioned in a separate seotion. 



Tbe t; . ' ^ and Mii- 



m^c^ivm. t ..-_.: . _ _ . . „_d 1923 ) to 



the drying and cooling treatments that he used for rotifers 

 (see aboreL In the dry state, all these tardigrades snr- 

 vived a cooling down to abont 1' K: when moist, they 

 resisted a slow cooling to the t«n|>eratQre of liquid hydro- 

 g&L. and >ome Ma^robiotms likewise supported a rapid 

 cooling to that temperature. Moreover, the dried tardi- 

 grades eonld withstand a sndden et»oling in liqnid air fol- 

 lowed by abrapt heating to 14fJ' to 151'. 



Bee*^nerel <1996) isolated the tardigrade, Macrobioins 

 Hvjtl^jK'^i. froan dried soils s"^ - for 71 honrs to 



t«nj»eratiires of — 269* to — 271 . ^ . : the details of the 

 experiment, see above, nnder the heading Botifers.) 



7. Amphibia amd Btptile?. That frogs and toads can 

 be revived -o'- _ " - i-n hard is a popular 



stalefmex.* f: :. l. Many observations 



and experiments are reported in the older biological lit- 

 erature which simply c-oirfinn this popular idea. Frogs 



ortc»: " f " - _•: " ■ * --^ -^ i-^ ^md. or maintained 



in Wi; . they l:>eeome inert 



and risid- are described as resuming activity when warmed 

 iipu 7 - " " these rexx»rts we tried the experi- 



n^^' - .... j:. ^-, wrapped in several layers of 

 cl :h- were pnt for S minntes into cavities dug in 

 solid earbon dioxide. The ^T^imalg became hard and rigid 

 like dead bc«"' " r. T:«eiiig re^ ". they regained 



movement ai. -. t. _:j. As we - by the follow- 



ing review, two important ste}>s were taken toward the 

 mjderstanding of the apparently high cold resistanc-e of 

 |,, — — -_--,-- _-. ^ ... -^ - ---;2:ators realized that a 

 r- . e a complete freezing, 



"i.-n they began to determine the internal temp>era- 

 ture of the animaLs during cooling. The time necessary 



