BY JAMES TOLSON, ESQ. 15 
“«« The putrescible liquid thus gives rise to two very distinct kinds. 
of chemical action, which have reference to the two sorts of organ- 
isms which are nourished in it. On one hand, the vibrios, living 
by the co-operation of the oxygen of the air, set up in the interior 
of the liquid acts of fermentation, that is to say, they transform 
the nitrogenous matter into more simple but still complex products. 
The bacteria (or the mucors), on the other hand, consume these 
same products, and bring them to the state of the most simple, 
ordinary combinations—water, ammonia, and carbondioxide.’ 
“«Summing up the experiments made by Pasteur, it may be said 
that putrefaction is always accompanied by the presence, the 
development, and the multiplication of infinitely small organised 
living beings; and, on the other hand, whenever we place the 
organic substances under such conditions that the germs or organ- 
isms are entirely excluded, or rendered dormant, decomposition 
can be indefinitely postponed, even in those products which are 
most liable to it. 
‘Two orders of phenomena are to be distinguished in putre- 
faction ; some are produced under the influence of those organisms 
which can exist and increase without the presence of oxygen; 
others, on the contrary, require oxygen, and can only develop in 
its presence, the resulting products being of a simpler composition 
than the substances from which they are derived. It is, in fact, a 
gradual degrading of the highly complex organic compounds, and 
results in their being finally separated into the original simple 
elements from which all organic substances are built up, namely, 
oxygen, hydrogen, and ape ra aia sc aapaegieanae Op. cit. 
Ahad PROCESS OF REFRIGERATION. 
The process of refrigeration is thus shown to be the 
removal of a certain quantity of the molecular motion of 
the substance operated upon. As already seen, radiation 
and contact of cold air are the two channels through which 
the heat will pass away, conduction, in our case, being only 
available in bringing the interior heat to the surface. 
In order that eehon may exercise the fullest effect, it 
is necessary that the bodies to be chilled shall radiate their 
heat to the walls or to some solid body, and not to them- 
selves. If by reason of their number and contiguity, 
straight lines drawn from any one of the bodies shall fall 
upon any of the others, the heat that would radiate from 
this body in the direction of the straight lines will not be 
removed but exchanged, and consequently radiation will 
