DECEMBER 13, 1906 | 
NATURE 
SOCIETIES AND ACADEMIES. 
LONDON. 
Royal Society, June 23.—‘' The Pharmacolozy of Ethyl 
Chloride." By Dr. E. H. Embley. 
Four years ago Dr. Embley published the result of an 
investigation into the pharmacology of chloroform which 
he had carried out in the physiological laboratory of the 
University of Melbourne,’ primarily with the view of 
elucidating the cause of those sudden misadventures which 
occur in chloroform administration, and more particularly 
during the early period of the induction of the anzesthetic. 
Dr. Embley’s work, however, covered the whole subject 
of the physiological action of chloroform in a very thorough 
manner, and perhaps one of the most striking merits which 
it possessed was due to the fact that the experiments were 
conducted throughout with definitely known percentages of 
chloroform in the air respired. 
The present work on ethyl chloride is conducted in the 
same quantitative manner, and with the same command 
of physiological technique, as shown by the excellent 
graphic records which illustrate the paper. 
Ethyl chloride was first used as a general anesthetic in 
1848 by Heyfelder. It subsequently fell into disuse, but 
was revived in 1895. Its position is intermediate between 
nitrous oxide and chloroform or ether. 
According to Embley, blood absorbs more than twice 
as much of the gas as water under similar conditions, so 
that ethyl chloride, like chloroform, evidently enters into 
loose chemical union with the blood. 
The first point ascertained was the direct effect of ethyl 
chloride upon the mammalian heart. 
Isolation of the heart was obtained by ligation close to 
the aorta of all the systemic arteries, except the sub- 
clavian. 
the heart, lungs, and one limb; the nervous system being 
cut off from its blood supply is instantly put out of action. 
The pressure in this miniature circulation was recorded 
by a manometer connected with one carotid artery. 
The effect of ethyl chloride upon heart muscle, as is 
the case with chloroform, and in contrast to ether, was 
paralytic, but the quantity of ethyl chloride vapour in the 
air required was nineteen times as great as that of chloro- 
form to produce comparable results. 
The direct influence of ethyl chloride upon the arterioles 
was demonstrated by driving an artificial circulation first 
through the isolated lungs and then through the isolated 
intestine of an animal, and measuring the outflow before, 
during, and after the admixture of definite percentages 
of ethyl chloride in the air rhythmically pumped into the 
lungs. 
The administration of air containing 20 per cent. to 
30 per cent. of ethyl chloride was found directly to 
paralyse the art-rioles. The effect upon the vasomotor 
system in the in,,ct animal was studied by taking simul- 
taneous records of the arterial blood pressure and of the 
volume of various organs. These experiments showed that 
with 20 per cent. to 30 per cent. ethyl chloride in the air 
respired, a considerable aegree of paralysis of the vaso- 
motor system occurred. 
Vagus inhibition of the heart was found readily to occur 
when above g per cent. of ethyl chloride vapour was present 
in air. Between ro per cent. and 20 per cent. inhibition 
caused sudden fall of blood pressure and cessation of circu- 
lation. These effects upon the heart were due to stimuli 
passing down the vagi from the central nervous system, 
for on cutting these nerves the circulatior, was instantly 
resumed. This sudden inhibition of the heart was not, 
however, nearly so dangerous as the same effect easily 
produced by chloroform, for the direct paralytic effect of 
ethyl chloride upon the heart muscle is comparatively 
insignificant, so that in the majority of cases recovery of 
the circulation readily occurred if the administration were 
suspended. : 
The effect of ethyl chloride upon the respiration is also 
dealt with. Ethyl chloride gradually reduces the rate and 
extent of the respiratory movements, and if pushed in 
sufficient concentration will ultimately lead to their cessa- 
tion. The same interdependence between respiratory 
1 **The Causation of Death during the Administration of Chloroform” 
(British Medical Journal, April 5, 12 and 19, 1902). 
NO. 1937, VOL. 75 | 
| 
By this procedure the circulation was confined to | 
_ that line and temperature. 
activity and blood pressure was brought out, as had been 
shown by Leonard Hill and the author, to obtain in 
chloroform poisoning. Provided the circulation were main- 
tained, it was found nearly impossible to produce cessation 
of respiration, but directly serious fall of blood pressure 
occurred, Owing to inhibition of the heart, the respiration 
immediately became very shallow or ceased, but returned 
again directly the circulation recovered. 
The primary danger in the administration of ethyl 
chloride to dogs, as in the case of chloroform, is syncope 
from inhibition of the heart, brought about by the stimu- 
lating action of these drugs upon the cardiac-inhibitory 
centre in the medulla. As it is a stimulating action, it is 
more prone to occur in the early stages of administration 
before these nerve centres are themselves narcotised by 
the drug. 
“ Refractive Indices of Water and Sea-water.’’ By 
ie Gifford. Communicated by W. A. Shenstone, 
.R.S. x 
Reference is made to previous papers (Roy. Soc. Proe., 
February 13, 1902, and March 3, 1904). The same special 
method of observation has been adopted. Measurements 
of the refractive index of water for twenty-six wave-lengths 
and of sea-water for twelve wave-lengths are contained in 
the paper. Those of sea-water were made for the purpose 
of computing an under-water lens, since successfully con- 
structed for submarine use. The measurements were 
made at an approximate temperature of 15° C., but were 
also. corrected by means of temperature refraction 
coefficients. 
The error is estimated as in no case exceeding 0:000025, 
and in most cases not exceeding o-oooo1s. The index of 
water for line D, reduced to 20° C. by the temperature 
coefficient, is 1.333032. Dufet (‘‘ Recueil de Données 
numériques,”’ vol. i., p. 83) gives 1-33303 as the mean of 
the measurements of twenty-nine different observers for 
The measurements were made 
on the goniometer used before (loc. cit.), but have been 
checked by critical work on a much larger instrument. 
The distilled water was prepared in platinum vessels by 
Mr. Bousfield; the sea-water was taken five miles from 
shore by Lieut. E. R. G, Evans, R.N. 
November 8.—‘‘ On a Compensated Micromanometer.’’ 
By B. J. P. Roberts. Communicated by Sir John I. 
Thornycroft, F.R.S. 
The principle of the gauge is similar to that of Sir W. 
Siemens’s bathymeter. The instrument described consists 
of a U tube having the limbs connected by a tube of 
small bore, the motion of the fluid in this small-bore tube 
being rendered visible by means of an air-bubble index. 
The sensitiveness depends on the ratio between the bores of 
the limbs and the connecting tube, and also partly on the 
nature of the fluid employed. The fluid should have a 
low surface tension, and the bore of the connecting tube 
should preferably not exceed 1-5 millimetres. The length 
of the bubble should be made equal to the distance between 
the centres of the upright limbs—the readings will then 
be practically unaffected by changes of level; the readings 
are also indifferent to vibration or similar disturbing 
causes. No fluid will pass the bubble provided certain 
precautions are observed—of these the most important is 
keeping the rate of movement of the bubble from exceed- 
ing certain limits. An attachment for preventing loss of 
fluid by evaporation is suggested in some cases. 
“The Composition of Thorianite and the Relative Radio- 
activity of its Constituents.”’ By Dr. E. H. Biichner. 
Communicated by Sir W. Ramsay. 
Various investigations on residues from the mineral 
thorianite, carried out in the laboratory of Sir William 
Ramsay, made it desirable to analyse a large amount of 
this mineral, and to determine how its radio-activity is 
distributed over its constituents. About 24 grams were dis- 
solved in boiling nitric acid, and left only a small residue 
behind, which was then fused with hydrogen potassium 
sulphate. The fused mass dissolved almost completely in 
water. The solutions obtained were then treated in the 
ordinary way and separated in the various groups. Pb, 
CuysSayeob.) Be vAl) Ur; Gh, Gey Zr, Ti, Ca, He €O;, 
and water were quantitatively determined; the greater part 
of these elements are present in very small quantities. 
