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superheated air at 15 inches pressure. Both of the tubes 
were kept until March, 1871. On opening the one which 
had not been heated, air rushed into it with great force. Its 
contents had a putrid smell, and the liquid on microscopical 
examination was found to contain numerous bacteria. When 
the superheated tube was opened, the ingress of air was 
equally forcible, but on microscopical examination no trace 
of organic forms could be discovered. 
From this experiment it would appear that diminished 
tension has no very considerable effect on the process we are 
studying. It is further evident that the non-appearance of 
organic forms in superheated liquids cannot be accounted for 
by supposing that it is attributable either to the relatively 
large proportion of the liquid, as compared with the volume 
of the air which is enclosed with it, or to any other circum- 
stance arising from its being contained in so small a receptacle. 
A third experiment of the same kind was made on August 
30th. A number of capillary tubes were filled with Pasteur’s 
solution, and then sealed and introduced into a large tube, 
closed in the same manner as in the previous experiment. 
The whole was then subjected to a temperature of 170° C., 
after which the contained tubes were broken by shaking. 
On examining the liquid contained in the broken capillary 
tubes after several months no organic form could be detected. 
The above observations (I to IV) show conclusively that no 
evolution of organisms took place in the superheated liquids, 
provided that the air with which they were in contact had also 
been superheated, whether they were kept at an ordinary 
temperature or at that of the body ; and that the effect was not 
modified, either by the tension of the air or by its quantity 
as compared with that of the liquid ; and it is further shown 
that in all the experiments, organisms appeared in the same 
liquids kept under precisely similar conditions, which had 
not been superheated. Before, however, drawing any further 
conclusions from these facts it may be inquired, in how far 
the cause of the non-appearance of organic forms is depen- 
dent on the liquids having undergone chemical changes of 
such a nature as to render them incapable of supporting life, 
in which case the negative results obtained could not be 
attributed exclusively to the non-exposure of the liquids to 
external media. It will be shown in the sequel that this is 
true as regards microzymes, that is to say, that superheated 
organic liquids are incapable of supporting the life of these 
organisms. It is therefore clear that such liquids do not 
furnish a suitable soil for studying the question we have in 
view. With respect to fungi, however, the case appears to 
