176 REPORT—1868. 
young trout in quantity, and so secure a very good inquiry. I hoped at first 
to be able to see the motion of the heart on a screen, by placing the animals 
in a trough in the oxyhydrogen lantern; and I have to thank Mr. Pepper 
and the Managers of the Royal Polytechnic Institution very heartily for 
placing their very perfect optical chamber at my service. I could not, how- 
ever, carry out in this way all I desired; for when the figure of the animal 
was projected on the screen, there were no visible movements except those 
of respiration. I therefore turned to the microscope, and found here all I 
could require. To carry out my plan properly, Dr. Sedgwick was so good 
as to devise for me a little trough, in which the trout could be placed for 
observation, and through which water charged with the required compound 
could be passed in a steady stream. ‘This plan prevented the accumulation of 
carbonic acid; and when no foreign substance was introduced into the cur- 
rent, the circulation and respiration of the fish could be observed for long 
periods naturally. 
Thus provided, three substances from one series were made to act upon 
the trout, viz. chloroform, ether, and chloride of methyl. The observations 
were most interesting, but to give them in detail would be too long; I shall 
therefore only offer the results in an abstract, which Dr. Sedgwick, who had 
the observations daily before him for several weeks, has been good enough to 
draw out for me. 
When chloroform is added to the water in which the young trout is living, 
in amount sufficient to destroy life in half a minute, the heart ceases acting 
at once, stops in diastole, full of blood. The gill and blood respiratory 
routine continue some little time afterwards. No contraction of extreme 
vessels is noticeable for some time after death. If the chloroform be added 
in smaller quantities, the first effect is violent struggling, which by degrees 
subsides. The respiration is at first much quickened, then becomes slower, 
and finally ceases—that is, so far as the gill, fin, and jaw motion is con- 
cerned. The heart at first beats quickly, then slowly, after a time intermits, 
and then totally ceases to act. No contractions of minute vessels could be 
observed under a power of 600 diameters. Not one of these fishes recovered 
from the narcotism of chloroform after the respiratory movements had ceased. 
With chloride-of-methyl gas in water, on the other hand, and also with 
ethylic ether, recovery was observed after all external respiratory movements 
had ceased, even for fifteen minutes, the heart beating all the time, but very 
slowly, the contractions reduced from 246 to 15 in a minute. The pheno- 
mena observable in these animals when narcotized with chloride of methyl 
is in other respects like those which occur under the use of chloroform, the 
notable points being the cessation of respiratory movements before the cir- 
culatory, and the absence of any definite contraction of the small vessels when 
the agents are administered in quantities not sufficient to produce immediate 
death. 
These experiments prove, I think, beyond cavil, that the chlorides of the 
methyl series do not of necessity destroy life by their direct action upon the 
heart. Indeed they indicate rather that when the heart itself is sound, 
and the chloride is let into the system by the process of inhalation, the heart 
is not primarily interfered with. It was therefore all-important to learn 
whether the heart could be primarily arrested by making it the primary 
recipient of the narcotic. 
To test this, a large animal was selected, and a twenty-minim dose of 
chloroform was slowly instilled, by one of Mr. Hunter’s syringes for sub- 
cutaneous injection, into a large vein in the ear. Within a few seconds 
