The Ilelminthos, Monlezia, Ostertagia, Nematodinis 

 and TricJiostrojipifhis, wore reported ])y Griffiths (19.'37) 

 to resist the coUl ol' a Canadian winter in wliich the tem- 

 perature reached -26°, and to l)e eapal)k', llie next spring, 

 of infecting- the grazing sheep. 



Augustine (1932) subjected to freezing f rich i nous meat 

 that he fed to experimental animals on which he studied 

 the subsequent infection. The temperature within the 

 meat was recorded with tliermocouples. lie found con- 

 siderable infection after exposure of the meat to - 21°, less 

 after exposure to - 27.6° to - 30.9°, and none after the 

 action of a temperature of - 33.7°. 



Rahm (1920, 1921, and 1923) observed that the newa- 

 todes, Pled us, Tylenchus and Dorijlaiunis, in the dry state, 

 could be cooled without injury to tlie lowest available 

 temperatures (boiling helium), and that in the moist state, 

 they resisted a slow cooling to the temperature of liquid 

 hydrogen. The author did not mention the revival of any 

 nematode after a rapid cooling to the latter temperature. 

 The dried worms, heated to 136° or to 151° and then cooled 

 abruptly to - 190° or to - 81°, died; they supported a heat- 

 ing to 50° followed by a sudden immersion in liquid air. 



3. Rotifers. The last-mentioned author {loc. cit.) ex- 

 posed to - 80° for 17 hours specimens of moss with their 

 natural fauna which consisted, among other organisms, 

 of rotifers belonging to the genera Callidina and Adi- 

 neta. The material, air-dried for periods extending from 

 18 days to 14 months, was immersed directly in a bath of 

 ether and solid carbon dioxide. All the organisms sur- 

 vived and resumed motion when remoistened. In other 

 experiments, the temperature of liquid air for ^, 5!, 25, 

 26 or 125 hours, that of liquid hydrogen for 26 hours, or 

 that of liquid helium (- 269 to - 271.88°) for 7^ hours was 

 found harmless to the dried animals. A previous desic- 

 cation of 3 months and a stay of a week in a vacuum of 

 1 10 mm. of mercury did not change their cold resistance. 



While the ])receding observations of Rahm are in good 

 fitting witli tliose made by other investigators on dried 



