The Sun.
London, England, 1858-10-11 00:00:00

PRUSSIC ACID.

With a view to complete the theory of
=esthetics, M. Ozanam some time ago insti-
tuted a series of experiments on prussic or
hydrocyanic acid in a gaseous state, the results of
which he has now laid before the Academy of
Sciences. His chief object was the demonstra-
tion of this general law, viz., that all volatile or
gaseous matter having carbon for one of its consti-
tuents has anmsthetic properties in proportion to
the carbon it contains ; and this law is verified in
the highest degree by hydrocyanic acid. In its
most concentrated state death of course is instan-
taneous, but when diluted in the ratios of 1 to 5, 1
to 20, 1 to 40, or 1 to 100, its effects are of various
intensity. The temperature must be taken into
account, since prussic acid boils at 27 degrees cen-
tigrade (80.6 Fahr.), and emits Tapours in propor-
tion to the heat of the weather ; M. Ozanam's ex-
periments were therefore conducted under tem-
peratures of between 5 and 10 degrees centigrade
(41 and 50 Fahr.) If attenuated to 1-40th, hydro-
cyanic acid produced, when inhaled, much the
same degree of anaesthesia, as oxade of carbon, and.
at 1-100th that of carbonic acid ; but this state can-
not be prolonged, as in the case of the latter—the
inhalation must be stopped the moment the first
signs of the action of the acid appear. The animal
being then left to itself, the three stages of anaes-
thesia, viz., excitation, collapse, and a return to
consciousness, succeed_ each other as usual. But if
the inhalations be continued to the second period of
coma, death is the inevitable consequence. The
stage of excitement is marked by such violent to
tanic shocks that the animal is often projected to a
distance of several feet ; the heart beats with great
rapidity, and respiration is interrupted by muscular
contractions. This state lasts from 30 to 60 secs.,
when the collapse commences, the eyeballs arc
ra-
pidly
dilated, the eyes protrude from their sockets,
and all the members are paralysed. But while
sharp instruments and hard blows are unavailing
to rouse the animal from its state of insensibility, a
slight shock is sufficient to cause a renewal of
the convulsions. During this period the action
of breathing only manifests itself by hiccups at
long intervals ; the pulsations of the heart are rare
and weak. By degrees, if too large a quantity of
the acid has not been inhaled, the circulation be-
comes more regular, and there only remains an
anaesthetic slumber which lasts from 5 to 15 mi-
nutes. After this there is a slow return to sensi-
bility, the animal begins to move its fore legs first
and its hind legs afterwards, about 25 minutes after
the commencement of the experiment, it returns to
its previous normal state. When death has been
produced
theby b edxyc, eisss ifvo eu n idn ht
oa
ba
et i obnl
a,
otkh, eb
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soon
turns red again in the air. The smell of bitter
almonds, which the body at first exhales, disappears
in a short time, and no trace of the acid can be dis-
covered by any test. Prussic acid would therefore
be the only poison producing death without being
traceable, were it not that the microscope shows
the primitive nervous tubes broken in various places.
Sometimes also the larynx and trachea are slightly
inflamed. M. Ozanam concludes his paper by stat-
ing that oxygen is an effectual antidote against
prussic acid. Until respiration is entirely stopped,
oxygen may. be successfully administered by inha-
lation, but it must be administered for 10 or 12
mptoms reappear.
minutes at least, else the sy