4 
I will now give his own description of the process, the prin- 
ciple consisting partly in the sterilization of the air in which fruit 
is kept through compression, and partly in the lowering of the 
temperature by the subsequent expansion of this compressed air. 
In the mechanical compression of air, if sufficient force be applied, 
its temperature may be raised to 200 degrees, or even 240 degrees, 
according to the extent of the power employed. The great heat 
has a germicidal effect. The microbes or living germs which 
induce the decay of the fruit or other perishable substances are 
thus destroyed. When the imprisoned air is relieved from pres- 
sure the resulting expansion rapidly lowers the temperature. It 
is even practicable by a sufficient concentration of the force of 
compressed air to induce actual freezing of a body exposed to an 
escaping jet. Dr. Perkins’ method, allowing the compressed air 
to expand in a fruit car or other confined space, is claimed to be 
practicable in maintaining a temperature of 45 to 60 degrees in 
the hottest weather, with a constant circulation of dry sterilized 
air through the chamber. 
The doctor supplemented this with the following additional 
information:— 
The Perkins sterilized dry-air process for the conservation of 
fruit, vegetables, &c., is the result of experimental study, and is 
the development of natural laws by mechanical methods. Instead 
of keeping the products in a close chamber, with a moist air and 
low temperature, they are placed in a continuous current of dry 
air at a normal temperature, or between 45 and 50 degrees Fah- 
renheit. The process is therefore diametrically opposed to refri- 
geration. The basis of action is on the prime factors of decay, 
which in fruit are a given percentage of sugar and acid, with a 
known degree of temperature and humidity, and in connexion 
with these the vitalizing and growth of the fungoid spores. 
These have been carefully studied. Other factors, viz., the elec- 
trical influence, &c., will be developed later. In illustration, the 
development of decay in fruits of fine tender flesh, rich in fruit 
juices, as the peach or apricot, is the action of the sugar and acid 
in fermentation, causing an exudation of moisture to the surface. 
Under a high temperature this is rapid, especially if the atmo- 
sphere is humid. This exudation is essential to the vitilization 
of the resting spores, and in fruits carrying a high percentage of 
sugar is correspondingly vicid, catching and retaining the floating 
spores in the atmosphere. 
The proper conservation of fruits requires a process which will 
produce the proper temperature to retard fermentation, a dry air 
to absorb the moisture, and a sterilized air to destroy the germs 
of fungoid growth, at least to devitalize those that may have 
formed the union of the hyphea, and to thoroughly sift and destroy. 
the floating spores. The process of refrigeration reducing the air 
to a low temperature, either by ice or chemicals, with a large 
degree of humidity, and sealed in a tight chamber, is imperfect 
