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carbon monovide there, might upon recovery be
used in an atmosphere containing a proportion
that does not usualiy affect a fresh animal. Finally
the same animal might be exposed over several
successive days while a mine was being explored.
It is believed that the experiments performed
show that animals will not be become acclimatized
to carbon monoxide under the conditions
surrounding recovery work in mines, and hence
become less useful and even a source of danger.
It might be mentioned that this question has been
raised several times in discussing the use of small
animals for detecting after-damp in mines.
It should be mentioned that the two Canadian
investigators, G. G. Nasmith® and D. A. S. Graham,
found that the aoimals finally become acclimatized
by continued exposure, i. e., if a guinea
pig is exposed for days or weeks to small percentages,
it can finally stand exposure that
would otherwise kill it, but our tests have shown
that in the case of small animals which are quickly
removed to fresh air (after distress is shown)
and then exposed again for a reasonable number
of times, this acclimatization effect is not apparent.
The two methods of experimentation are not parallel.
It is pertinent to add that the effect Nasmith
and Graham observed in guinea pigs—an
increase in the red-blocd cells—has been observed
in men working around blast furnaces. Blastfurnace
gas contains a high percentage of carbon
monoxide.
EFFECTS ON THE DIFFERENT AXI.MAI.S OF THE SAME
PROPORTIONS OF CARBON MONOXIDE.
The Bureau has performed many experiments in
order to draw some conclusions regarding the effect
on different animals of the same species of a given
proportion of carbon monoxide. It was found
that in general a given proportion of carbon monoxide
affected different animals of the same species
in about the same length of time, at least as far as
the application of the results to the practical use
of the animals in mines is concerned, but that
once in a while an animal might behave markedly
different from what is expected. This is truer
of mice than of canaries, yet even in the case of
the latter several of them should be taken with an
exploration party.
HIE RELATIVE EFFECT OF SMALL AMOUNTS OF CARBON
MONOXIDE ON MEN AND SMALL ANIMALS.
In reading over accounts of rescue and recovery
work in mines, one is impressed with the fact
that some users of small animals have not been
entirely satisfied with the behavior of mice and
©The haemotology of carbon-monoxide poisoning.
Jour. Physiology, 1906, vol. 25, Nos. 1 and
2, pp. 32-52.
THE COAL TRADE BULLETIN. 57
birds, (especially mice), in that men have apparently
felt distress before the animals became affected.
The Bureau as the result of many experiments
made to determine the resistance of
small animals to carbon monoxide poisoning believes
it has the data at band which explains this
dissatisfaction.
It was found, for instance, that almost all of
the animals tried do not show sufficient distress
in one hour's time with 0.10 per cent, of carbon
monoxide to make them valuable for detecting
this percentage of the gas. In some cases the
length ot exposure was extended to three hours
without any effects being observed. In one case
only was a canary affected in so short a time as
12 minutes by 0.10 per cent, of carbon monoxide.
With another bird and tbe same percentage of
carbon monoxide, distress was scarcely observable
in three hours. Only a disposition to remain
quiet was observed. Eight different canaries
were used and six different mice. Only onemouse
out of many was slightly affected in so
short a time as 10 minutes with 0.10 per cent.,
but was not overcome in four hours. Neither
chickens nor pigeons were visibly distressed.
With 0.15 per cent, both canaries ancl mice began
to be affected. With 0.15 per cent, carbon monoxide
canaries showed distress in from 5 to 30
minutes. A mouse showed slight distress at the
end of an hour. With 0.20 per cent, canaries
responded in from two to five minutes except in
one case (35 minutes). Three mice responded in
12 minutes, and a fourth one in 46 minutes. No
blood tests were made, tbe object being to determine
tbe usefulness of the animals for mining
work, where their behavior as apparent to the
eye is the only guide. Haldane states that 0.06
per cent, carbon monoxide is sufficient to produce
distress symptoms in mice.® The author of
this paper does not hesitate to say that because
of his greater experience in experimenting with
small animals Dr. Haldane might detect outward
symptoms in a mouse that would escape the
author's attention. On the other hand, the author
has had greater experience than many of
those who might use small animals in mines.
Further, in the laboratory, observations are better
made than in the mine where the light may be
poor. Dr. Haldane made many experiments
with himself as the subject in determining the
effect of carbon monoxide on men.® He found
that 0.12 per cent, causes a mouse to sprawl in
©The relation of the action of carbonic acids
to oxvgen tension. J. S. Haldane. Jour. Physiology,
vol. 18, 1895, pp. 201-217.
®The action of carbon monoxide on man. John
Haldane, Jour. Physiology, vol. 18, 1S95. pp. 430-
462.