LATENT LIFE—BECQUEREL. 547 
seeds and spores in their state of natural desiccation endure, without 
perishing, temperatures as low as 190° to 250° below zero. I myself 
in attempting to ascertain the influence of the state of hydration, of 
decortication, and of gaseous reserves of the seed, have obtained 
analogous results. The investigators above mentioned, believing 
that physical and chemical phenomena are completely suppressed by 
low temperatures, have thought that the latent life of seeds and 
germs plunged into liquid air or hydrogen must be a completely 
suspended life. But this opinion should be accepted with some 
reserve. Certain chemical reactions may still take place at low 
temperatures. Have not Dewar and Moissan shown that solid 
fluorine in contact with liquid hydrogen is combined explosively at 
250° C. below zero? On the other hand, Svante Arrhenius ! does not 
now admit the suppression of chemical reactions at that temperature. 
He considers that the chemical reactions especially connected with 
the loss of the germinative power of seeds must be much retarded 
by cold. Upon the basis of the experiments of Nyman and Madsen 
in which the spores of anthrax are shown to develop twice as rapidly 
when the temperature is increased 10°, the eminent Swedish physicist 
formulated an ingenious hypothesis according to which the retarda- 
tion of life should be twice as great if the temperature is lowered 10° C. 
According to this rule the germinative power of spores would diminish 
no more during 3,000,000 years at 220° below zero than during a single 
day at 10° above zero. 
If we accept this calculation and apply it to macrobiotic seeds which 
live a hundred years at a temperature of 10°, their latent life, pro- 
vided it could be kept at a temperature of 220° below zero, could be 
prolonged for two hundred billions of years. This is a number which 
surpasses any which is conceded for the duration of life on the surface 
of the earth, and even for the period of the evolution of our solar 
system. 
If the physical and chemical phenomena of life are thus retarded, 
we concede that we could not detect it experimentally. 
But since in all the experiments with low temperatures upon which 
Arrhenius relies, it is a matter of germs in the state of natural desic- 
cation, containing consequently from 5 to 12 per cent of their weight 
of water, it is interesting to ask what would happen if we were to 
experiment with dried seeds placed in the most complete vacuum 
and submitted at the same time to the lowest temperatures. With 
this in view, with the valuable cooperation of the learned physicist 
of Leyden, M. Kammerlingh Onnes, who very kindly placed at my 
disposal the resources of his excellent cryogen or refrigerating labor- 
atory, there were submitted for three weeks to the temperature of 
1 Svante Arrhenius: L’évolution des mondes (translation by Seyrig), p. 138. 
