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open and kept in the laboratory. 4 were sealed and raised 
to a temperature of 200°C. Some of them were afterwards 
placed in the incubator, others remained at the ordinary 
temperature. Specimens of a and 4 were examined at various 
periods up to March, 1871. All of the tubes a became turbid 
sooner or later, and were then found to be crowded in different 
degrees with bacteria and fungi (torula cells and mycelium). 
When the remaining tubes were finally opened it was found 
that in many of them gas had been disengaged in such 
quantity, that when the end of the tube was broken off the 
liquid was expelled with violence. In others this evidence 
of increased tension was wanting. On comparative micro- 
scopical examination it was found that the liquid in these 
last, contained no torula cells. 4 were kept till March, 1871, 
at which time they were found to exhibit no trace of organic 
life, whether they had been kept in the incubator or at the 
ordinary temperature. 
IV.—August 18.—It has been imagined that the so-called 
spontaneous evolution of organic forms is materially increased 
when the air to which the liquid is exposed has a tension 
much inferior to that of the atmosphere, and conversely that 
in liquids subjected to pressures greater than that of the 
atmosphere the development of such forms is arrested. The 
following experiments were made to test this supposition. 
Several capillary tubes were filled with fresh serum of blood 
of a rabbit kept in an ordinary clean glass. These were 
sealed and placed in a larger glass tube closed at one end, 
which after having been drawn out at a short distance from 
its open end was attached thereby to one branch of a T tube 
by means of a vulcanite junction. The stem of the T tube 
was then connected with an air pump, and the other branch 
with a long barometer tube standing vertically in a cup of 
mercury. ‘The air was then exhausted, and as soon as the 
mercury had risen in the barometer tube 15 inches, the flame 
of a blow-pipe was directed against the narrow drawn-out 
part of the experimental tube, which was thus sealed while 
the air which it contained had a tension not more than half 
that of atmospheric air. The tube was then shaken so as to 
break all the capillary tubes, so that the whole of the liquid 
which they contained was exposed to the pressure above 
indicated. It was then kept at the ordinary temperature. 
Another tube was filled with capillary tubes containing 
serum, exhausted to 15 inches, and closed hermetically in 
the same way. It was then placed in the oven and raised to 
a temperature of 200° C., after which the capillary tubes 
inside were broken as before, so as to expose the liquid to 
