THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[December 28, 1872, 
<514 
THE MEDICAL SOCIETY OF THE COLLEGE 
OF PHYSICIANS, DUBLIN. 
Wednesday , April 24 th, 1872. 
The Afflicajion of Gases as a Means of 
Destroying Contagion. 
BY CHARLES A. CAMERON, FH.D., M.D., 
Professor of Hygiene in the Poyal College , etc. 
[Concludedfrom p. 494.) 
Before the question of bacteria as a cause of zymotics 
•arose, Haygarth, Murchison, Ryan of Lyons, and others 
denied that small pox poison was directly transmitted 
through any considerable space in the open air. Mur¬ 
chison asserts that the poison was not contagious in the 
open air at a distance of half a yard. Chauveau states 
that the contagious matter of small pox is volatile—that 
the solid particles float into the air at a temperature of 
40° centigrade, but in his experiments the matter was 
carried away by a current of vapour. The pent-up 
gases in a sewer when they find an outlet into a house 
undoubtedly often carry up mechanically the materies 
morbi whatever it may be, of enteric fever. 
It would appear that whilst minute plants and spores 
float about abundantly in the atmosphere, minute 
animals and ova adhere to walls and other solids. Now, 
in ordinary disinfection the principal object is to act 
upon the atmosphere. A bad odour is observed in the 
•sick-room wherein lies a small-pox patient, but that 
odour is not actually connected with the cause of the 
disease; the contagious matter which produces small¬ 
pox is odourless. We might destroy the bad odour in 
the room without diminishing the quantity of contagious 
matter present. 
The following experimental results prove that the 
ordinary disinfection by gases does not kill the bacteria 
which are usually associated with putrefaction, nor does 
it perfectly destroy the contagious matter of at least one 
zymotic disease:— 
. Several watch- and microscopic object-glasses were 
dipped into filtered beef-tea, which contained enormous 
numbers of bacteria, and whilst still moist they wei’e 
placed in different positions in a hood, or small chamber 
made of wood and glass, containing 16ij cubic feet of 
space. Half an ounce of chloride of lime was placed in 
.a capsule and introduced into the hood, and an equivalent 
quantity of hydrochloric acid was poured on the powder 
in such a way as to prevent the chlorine evolved from 
passing out of the hood. After the lapse of 24 hours 
the door of the hood was opened and the glasses removed. 
They were found to be covered with extremely thin 
films of solidified beef extract. A few drops of pure water 
were used to render the film semi-liquid, and its con¬ 
tents were examined with a microscopic power of 800 
•diameter. In a few seconds the bacteria were detected 
moving about with great rapidity, and with apparently 
undiminished vigour. It was clear then that fumigation 
at the rate of a little more than three ounces of bleach¬ 
ing powder per 100 cubic feet of space had no effect in 
destroying bacteria. The hood was more air-tight 
than a room is when its doors, windows and fire-place 
.are closed. On opening the door of the hood after 24 
'hours the odour of chlorine was distinctly perceived at 
a distance of several feet. If a room 15 feet long, 10 
feet wide, and 10 feet high, and having, therefore, a 
•capacity of 1500 cubic feet, were disinfected by chloride 
•of lime in the relative proportions employed in the fore¬ 
going experiment, it would be necessary to use nearly 
three pounds of chloride of lime. 
As the gases evolved from three ounces of bleaching 
powder per hundred cubic feet of space did not destroy 
bacteria,, an experiment was made with one ounce per 
16^ cubic feet, or at a rate of nearly six pounds per 
1500 cubic feet—the size of a small room. The result 
was similar to that of the first experiment, the bacteria 
being almost as lively after as they were before the 
process. 
The next quantity tried was one and half ounces of 
bleaching powder per 16 J cubic feet, or at the rate of 
about eight and a half pounds per room of 1500 cubic 
feet capacity. After 24 hours’ exposure to the highly 
chlorinated atmosphere produced by this experiment, the 
greater number of bacteria were not only alive, but 
most of them exhibited the utmost vitality. Two ounces 
of bleaching powder per 16| cubic feet were next tried, 
and after exposure to the gases evolved from this quan¬ 
tity by the action of an acid, the bacteria, though languid, 
were still mostly alive, and a few of them were very active. 
The last experiment was made with three ounces of bleach¬ 
ing powder per 16J cubic feet, or at the rate of 16£ 
pounds of the disinfectant to 1500 cubic feet; but even 
the enormous amount of gas evolved from this quantity 
failed to kill the greater number of the bacteria sub¬ 
jected to its influence. Films of moist meat extract 
containing bacteria were next exposed to an atmosphere 
of equal parts of chlorine gas and ordinary air. This 
operation was conducted on an air-tight glass vessel. 
After 24 hours they were examined, and no life could be 
perceived. Dried films of meat extract containing bac¬ 
teria were submitted to the influence of this gaseous 
mixture, but after being moistened many of the bacteria 
were found still alive though almost inactive. 
Similar experiments were made to ascertain the action 
of sulphurous acid gas upon bacteria, but this gas was 
also found to produce but little effect on these animal¬ 
cules. 
Having proved that the bacteria which exist in liquids 
are not destroyed by exposure to atmospheres highly 
charged with chlorine or sulphurous acid gas, an ex¬ 
periment was next made with the view of ascertaining 
whether or not the germinal matter of bacteria could be 
destroyed by ordinary gaseous disinfection. Accord¬ 
ingly filtered beef-tea, which did not exhibit any forms 
of life under the microscope, was divided into three parts. 
One portion («) was placed in an ordinary test-tube, 
and loosely plugged with cotton wool, another portion 
(5) was placed in a test-tube, which had shortly before 
been heated nearly to redness, and loosely plugged with 
cotton wool, which had been highly heated to 350°; 
the third portion (c) was poured upon microscopic ob¬ 
ject- and shallow watch-glasses, and these were placed 
in the hood and exposed for 48 hours to the gases 
evolved from two ounces of bleaching powder, treated 
with acid. In 24 hours the liquid ( d) which had simply 
been deposited in a test-tube, was found to swarm with 
microzymes; the liquid which had been placed in the 
tube that had been heated to redness was, after a week, 
found to be free from animal life,* whilst a few hours 
after their removal from the hood, the films of beef-tea 
exhibited swarms of vibriones, although every precau¬ 
tion was taken to prevent contamination from solid 
surfaces subsequent to the removal of the glasses from 
the hood. 
The following experiment was made in a room of 
1600 cubic feet capacity. Animal liquids containing 
microzymes were placed upon the chimney-piece, upon 
the window panes and other smooth parts of the 
apartment. Seven pounds of chloride of lime were then 
decomposed by oil of vitriol, and the room carefully 
closed up. After 48 hours the room was opened, and 
the films containing the bacteria were, with every pre¬ 
caution washed upon object-glasses, and examined micro¬ 
scopically. In every case there were large numbers of 
living microzymes. 
The next experiment was conducted as follows:— 
Four ivory points, charged with vaccine lymph, were 
* Dr. Sanderson has shown that animal liquids, deposited 
while fresh in tubes which had been highly heated, and 
loosely plugged with cotton wool, remained free from bacteria 
for a long time. 
