62 THE EVOLUTION OF LIFE 
arrived at a similar conclusion concerning Torulz. 
He said,' ‘‘A temperature of 60° C. kills the yeast 
cells ; after exposure to this temperature in water, 
they no longer undergo fermentation, and do not 
cause fermentation in a sugar solution. . . . In like 
manner active fermentation in a saccharine liquid is 
stopped when the liquid is heated to 60° C., and it 
does not recommence on cooling the liquid.” 
In the following year Professor Cohn and Dr 
Horwath made experiments almost similar to mine 
in regard to the death-point of Bacteria, but not of 
Torule. It does not appear that they were then 
aware of my prior investigations. They, however, 
arrived at results almost precisely similar, as may be 
seen when Professor Cohn says”: ‘These experi- 
ments demonstrated, without exception, that no 
Bacteria were developed in the flasks which were 
kept at a temperature of 60°-62° C. for an hour, and 
that the contained fluid remained clear; on the 
other hand, flasks containing bacterial fluid which 
had only been heated to 50° C. or go C. became 
clouded in consequence of the multiplication of 
Bacteria, in a time ranging from two to three days.” 
In the year 1873 I returned to this subject, in 
order to ascertain whether Bacteria would be killed 
at precisely the same temperatures in organic in- 
fusions as they had been in a neutral saline solu- 
tion. The question was how to operate with such 
1 Translation of a paper on “Alcoholic Fermentation,” in Pharma- 
ceutical Journal, July 30, 1870, p. 81. 
2 “ Beitrage zur Biologie der Pflanzen,” 1872, p. 219. 
