HEAT UPON LIVING MATTER. 135 
living tissues, turned from a clear fluid into an 
opaque solid ; and we have the ‘ yelk, made up of a 
dense aggregation of the simplest living units, also 
more or less solidified. In spite of the investing 
calcareous shell, these very obvious and: destructive 
effects can be produced upon this large egg or ‘germ’ 
by an exposure for three or fourr minutes: to the in- 
fluence of boiling water. Yet: the living matter in 
this case is so simple that it possesses next to no 
organization—it is so little vitalized that it can 
only be considered to be half alive. 
The conclusion would seem, therefore, to force itself 
upon us that there is something intrinsically dele- 
terious in the action of boiling water upon living 
matter—whether this living matter be of high or 
of low organization. 
This subject is one of great importance in many 
respects, so that it may repay us to look into the evi- 
dence bearing upon it with some degree of care. It 
-is of great practical importance, for instance, in refer- 
ence to the process of disinfection by heat, where we 
have to do with articles of furniture or wearing ap- 
parel used by a person suffering from a contagious 
disease. Because, in such a case, what we ought 
undoubtedly to know is whether the temperature of 
boiling water, or even some lower temperature, 
