material, llie results that he reports on moist rotifers are 

 probably not paralleled in the literature. When the dried 

 animals had resumed their motion after immersion in 

 water, they were frozen either slowly, by steps, to - 81°, 

 to - 190° and to - 253°, or rapidly by sudden immersion in 

 liquid air and in liquid hydrogen. After having stayed 

 2 days and 1 day respectively in the two last-mentioned 

 liquids, they could be revived, although the rapid refrig- 

 eration seemed to have lengthened the duration of the 

 recovery and to have been somewhat more harmful to 

 some individuals than w^as the gradual cooling. The 

 author remarks that possibly some organisms, counted as 

 survivors, may have been hatched after the exposure to 

 low temperature. This would, of course, modify the 

 problem entirely. 



In another series of experiments, Rahm succeeded in 

 maintaining alive some of the above-mentioned rotifers 

 after they had been thoroughly dried in air for a month, 

 then immersed in liquid air for 5 hours and finally heated 

 in an oven to 140° to 151° for 15 minutes. Heating the 

 dry organisms first and cooling them afterwards gave the 

 same results. 



Becquerel (1936) found the rotifers. Ad met a gracilis. 

 Rotifer vulgaris, and Calliftiiia a)igiisticoUis, alive in sam- 

 ples of soil previously dried in a vacuum for 3 months and 

 exposed to liquid helium for 7| hours and to liquid nitro- 

 gen for 480 hours, either in cotton-plugged glass tubes or 

 in highly evacuated sealed tubes. 



4. Anuelids. According to Doenhoff (1872), leeches, 

 exposed for 1 hour to a temperature of -1.5°, survived 

 though they had been frozen so stiff that they could be 

 bent only with difficulty. These animals, when cut with 

 scissors, exhibited a cross section whitish with ice. Simi- 

 larly, leeches exposed for 3 hours to -1.5° revived, but 

 could no longer crawl and died after a few days. Leeches, 

 subjected for a few minutes to - 6.25°, died. 



According to Schmidt and Stchepkina (1917), earth- 

 ivorms could be revived after an exposure of 8 hours to 



