Notes. 
589 
ON THE SUSPENSION OF LIFE AT LOW TEMPERA- 
TURES 1 . — Our first experiments were made with organisms possess- 
ing varying degrees of resistance, the extremes in this respect being 
represented by the sensitive Spirillum of cholera asiatica and the 
resistent spores of Bacillus anthracis . Ten organisms altogether 
were used and cooled down to — 190° C., in the first instance for 
twenty hours, and eventually for seven days. These exposures did 
not produce any appreciable impairment in the vitality of the organ- 
isms, either as regards their growth or their characteristic physio- 
logical properties, such as pigment and gas-production, pathogenicity, 
&c. Amongst the organisms tested were photogenic Bacteria, and 
these likewise preserved their normal luminous properties; and we 
were able, through the kindness of Professor Dewar, to apply a still 
severer test — namely an exposure to the temperature of liquid hydro- 
gen (about — 252°C.), a temperature which is as far removed from 
that of liquid air as is that of liquid air from the average summer 
temperature. Ten hours’ exposure to this temperature had no appre- 
ciable effect on the vitality of the micro-organisms tested. At such tem- 
peratures it must be assumed that the chemical metabolism of the cell 
ceases, in the absence of heat and moisture. At the same time it appeared 
to us advisable to test the influence of a prolonged exposure to low 
temperatures on the vitality of cells. The experiments were con- 
ducted with the aid of the liquid air plant at the Jenner Institute 
of Preventive Medicine. The organisms employed were the Bacillus 
typhosus , B. coli communis , Staphylococcus pyogenes aureus , and a 
Saccharomyces. The Bacteria were suspended in small loops of 
platinum wire or on cotton-wool swabs, and directly immersed in the 
liquid air. The yeast, washed and pressed, was wrapped in rice- 
paper, and likewise directly immersed in the liquid air. Samples 
were taken and tested at intervals for a total period of six months. 
In no instance could any impairment of the vitality of the organisms 
be detected. The yeast gave a good growth, and exhibited its 
fermentative powers unaltered; the typhoid Bacillus retained its 
pathogenic and other properties ; the Staphylococcus aureus gave 
a characteristic pigment growth, and the colon Bacillus responded 
to all the typical tests that were applied to it. Judging by the results, 
the experiments might have been prolonged for a much longer period 
1 Abstract of paper read before Section K of the British Association, Belfast, 
1902. 
SS2 
