1885.] on the Mechanical Production of Cold, dc. 315 



except the spores of bacilli, which survive exposure to as low a 

 temperature as — 15^ C, even when exposed for an hour or more." 

 Again, in another place, * he says : " Exposing the spores of anthrax- 

 bacillus to a temperature of 0° to — 15^ C. for one hour did not kill 

 them." 



In 1884 a remarkable series of experiments were described to the 

 French Academy, by MM. R. Pictet and E. Yung.-f These observers 

 sealed up in small glass tubes fluids containing various kinds of 

 microphytes, and placed them in a wooden box. The box was in the 

 first place submitted for 20 hours to a cold of -- 70^ C, produced by 

 the evaporation of liquid sulphurous acid in vacuo. The box was 

 then surrounded by solid carbonic acid for 89 hours, and a cold of from 

 ■- 70° to — 76° C. was thus obtained. Finally, the box was subjected for 

 a third period of 20 hours to a cold produced by the evaporation of 

 solid carbonic acid in vacuo — the temperature being estimated at from 

 — 76^ to — 130° C. — that is, a minimum temperature of 202° below 

 zero F. They sum up by stating that the organisms were acted 

 on by a cold of — 70° C. for 109 hours, followed by a tempera- 

 ture of — 130° for 20 hours. The organisms tested were Bacillas 

 anthracis, Bacillus suhtilis, Bacillus ulna, Micrococcus luteus, and a 

 micrococcus not determined. Bacillus anthracis retained its virulence 

 when injected into a living animal. The vitality of the others was 

 not affected. Experiment showed that, whilst cold seemed to kill 

 some of the micrococci, a great number resisted it. Yeast showed no 

 alteration under the microscope, but it had lost its powers of fermen- 

 tation. Vaccine lymph exposed to the low temperatures did not pro- 

 duce a pustule on the left arm of an infant, whilst another samj)le of 

 the same lymph introduced into the right arm of the same child pro- 

 duced a pustule. Pictet and Yung conclude, from their experiments, 

 that, in the conditions of cold indicated, many of the lower organisms 

 were not destroyed.^ 



From this concensus of evidence, Mr. Coleman observed, it then 

 appears that any hope of permanently sterilising meat by cold (the 

 counterpart of Appert's process by heat) must be abandoned, but it is 

 quite possible that at some point near absolute zero the vitality of all 

 microphytes may be destroyed. 



The persistency, however, of their vitality between great extremes 

 of temperature, ranging in fact through 400° F. is very remarkable, 

 and is in marked contrast to their susceptibility to destruction by 



* Klein, op. cit, p. 73. 



t Comptes Eendiis, Tome xcviii., No. 12 (24 Mars, 1884), p. 747. 



j lu a letter to Dr. McKendrick, Professor Arthur Gamgee states that some 

 months ago lie exposed putrescible fluids to moderate degrees of cold without 

 thereby preventing putrefaction, and that he abandoned the research as unlikely 

 to lead to any important result with the temperature he had at command. It is 

 also stated in Landois' Physiology, translated by Stirling, vol. i., p. 456, on the 

 authority of Frisch, that " bacteria survive a temperature of — 87° C. ; yeast 

 eveu - 100° C." 



