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penetrate into the depth was protected against the action of the formalin, whereas owing to
the thinness of the linen and paper the microbe could well be acted upon by the formalin.

Table VIII. gives in a comprehensive manner the general results of this series of
disinfection experiments, viz., with formalin for five hours. The + sign means positive culture
and experiment on animal after exposure, the sign — means failure to recover the microbe
in a living condition. It will be seen from this table that all the microbes exposed on linen
to the formalin were completely disinfected, and, with the exception of the spores of anthrax,
also on paper. Further, complete disinfection of the wood and the cloth was effected by formalin
except in three cases. One of these was in the first experiment with typhoid, when a broth emulsion
of it was used; in two later experiments, however, typhoid was completely devitalised. The
second case in which formalin failed to disinfect the wood and cloth was that of anthrax spores,
and the third that of tubercular sputum. This appears to be due to the greater thickness of,
and, therefore, imbibition into, the materials, and the consequently greater chance of escape
of some of the microbes from the attack by the formalin. In cases, therefore, where wood
flooring, unpainted or unvarnished articles of furniture, or similar absorbing materials and
cloth fabrics are to be subjected to disinfection on account of their being possibly polluted with
tubercular sputum, or highly resisting microbes like the spores of anthrax or other spores (e.g.,
tetanus), the disinfection with formalin alone will not suffice. But in the case of paper, linen,
or similar thin fabrics (calico) the disinfection with formalin (except spores of anthrax or
similar highly resisting spores) will presumably be attended with success.
Series II.—Sulphurous Acid Gas (Sulphur Dioxide).
The experiments with the sulphurous acid gas were performed in a room, the capacity of
which was 1,075 cubic feet; three pounds and a half of sulphur were burned in the middle of the
room on an ordinary " sulphur devil." As in the case of the formalin experiments the fireplace,
window, and door were carefully and accurately sealed up with pasted paper. The room
was left closed up for exactly 24 hours. The preparation of the microbes, their application on
the materials, wood, cloth, linen, and paper, and the treatment subsequent to the exposure were
exactly the same as in the case of the formalin experiments, and it is not therefore necessary to
repeat the details of the individual experiments.
1.—Bacillus Typhosus.
Table IX. gives the summary of the results in two experiments made with this microbe:
experiment (a), with an emulsion in broth, experiment (b), with an emulsion in separated milk.