74 THE ROYAL SOCIETY OF CANADA 
vitality in vacuo. Maquenne,! for instance, found that grains of wheat 
can withstand subjection to a vacuum of less than one-hundredth of a 
millimetre of mercury pressure for several months without losing their 
power of germination, and he suggested that under such conditions 
vitality may be completely suspended. The question of the entire 
suspension of vitality in the reproductive bodies of plants has been 
investigated anew in a very thorough manner by Paul Becquerel, who 
has published a series of papers on the subject in the “Comptes rendues.” 
He first found? that dried seeds of various kinds, such as peas, on being 
placed in pure and dry nitrogen in the dark for a year, did not liberate 
a trace of carbon dioxide, and yet germinated subsequently. In later 
experiments’ he has shown that the seeds of Lucerne, and of White 
Mustard, and also grains of Wheat, after having their coats perforated, 
can be subjected to total desiccation in a vacuum of one five-hundredth 
of a millimetre pressure of mercury for one year, and that during this 
period they can be subjected for three weeks to the temperature of 
liquid air (-190° C.), and for seventy-seven hours to the temperature of 
liquid hydrogen (-253° C.), and that, nevertheless, when subsequently 
they are supplied with air and moisture at a suitable temperature, they 
germinate in a normal manner. Becquerel came to the conclusion that 
his experiments, along with those of his predecessors, indicate that at 
least for the seeds upon which he experimented, an interruption of life 
is not only possible but actual, without there being any indication of 
the existence of a limit to its prolongation. Still more recently* he 
extended his investigations to the spores of certain moulds, (Mucor 
mucedo, M. racemosus, Rhizopus niger, Sterigmatocystis nigra, and 
Aspergillus glaucus). These were dried slowly, in the presence of caustic 
baryta, for two weeks at 35° C. The containing tubes were afterwards 
sealed to a Berlement mercury pump and evacuated as perfectly as 
possible; they were sealed off after a McLeod guage indicated a pressure 
of less than one-thousandth of a millimetre of mercury. The vacuum 
was maintained for twenty-five months, and during this period the 
spores were subjected to the temperatures of liquid air and liquid 
hydrogen for three weeks and seventy-seven hours respectively, as was 
done with the seeds. When the spores were subsequently placed upon 
sterilized nutritive media, they soon germinated in a normal manner, 
and a fresh crop of spores was quickly produced. 
* Maquenne, Compt. rend. 1902, T. 134, p. 1243. 
* Paul Becquerel, “ Sur la nature de la vie latente des graines et sur les véritables 
caractères de la vie,” Comp. rend. 1906, T. 143, pp. 1177-9. 
* Paul Becquerel, “Sur la suspension momantanée de la vie chez certaines 
graines,” Comp. rend., 1909, T. 148, pp. 1052-4. 
* Paul Becquerel, “ Recherches expérimentales sur la vie latente des spores des 
Mucorinées et des Ascomycetes,’ Compt. rend., 1910, T. 150, pp. 1437-9. 


