ACTION OF CHLOROFORM UPON THE HEART AND ARTERIES. 3138 
to it by Bownprrcu and Minor, viz., that of producing dilatation. In repeating and 
extending our experiments we have therefore included the effect of the perfusion of 
mammalian organs with various strengths of chloroform dissolved in Ringer's solution. 
Perfusion of Frog Vessels with Chloroform dissolved in Ringer’s Solution. 
The Ringer’s fluid used consisted of NaCl, 6 grammes; CaCl,, 0°1 gramme; KCl, 
0:075 gramme ; NaHCO,, 0°1 gramme per litre. The chloroform was either dissolved in 
this solution in proportion determined by weight, or some of the fluid was saturated by 
being shaken up with and kept over an excess of chloroform, and was assumed to con- 
tain 1 part chloroform to 200 Ringer, this being the amount water will take up at the 
ordinary temperature of the air (15° C.). This saturated solution was mixed with vary- 
ing proportions of normal Ringer. A fine cannula having been tied into the bulbus 
aortee of the frog (R. esculenta or R. temporaria), the fluid was allowed to pass by 
gravity, at a pressure varying in different experiments from 50 mm. to 150 mm. of 
water, through the vascular system, and to drip from the extremities of the toes. In 
our earlier experiments the mode of determining the rate of flow was to count the 
number of drops per minute; but this method, although serving to indicate any differ- 
ences of vascular calibre which are marked, is not sutftciently accurate for slight varia- 
tions, since the size of the drops is liable to vary somewhat with differences of surface 
tension of the fluid, and the amount of dissolved chloroform or of intermixed blood and 
lymph may affect its surface tension. In all later experiments, therefore, the amount 
of fluid perfusing in a given time was accurately measured. Only the results thus 
obtained are included in this communication. 
The result of these perfusion experiments with Ringer's fluid containing dissolved 
chloroform may be shortly stated as follows :— 
With the strongest solutions, .e., from saturated (1 in 200) down to solutions con- 
taining 1 in 500, a very marked constriction of the arterioles is the result of perfusing 
with chloroform-Ringer, so that the flow of the perfusing fluid becomes very slow, and 
may almost cease. With increase of dilution the amount of constriction, as registered 
by rate of flow, becomes less; but although very slight when the dilution is consider- 
able, we have been able to substantiate constriction with solutions as weak as 1 in 
20,000. On the other hand, no solution of any strength when perfused through the 
frog’s vessels has given evidence of dilatation of arterioles, the weaker solutions having 
simply shown themselves inert. If for the chloroform-Ringer which has been passed 
for some minutes through the vessels, and has produced the diminutions of flow above 
indicated, normal Ringer be now substituted, the flow again becomes more rapid, but 
the original rate is rarely again obtained; in fact, after the chloroform solution has 
been in action for some minutes, even if the strength of the solution be such as to 
be insufficient to cause actual constriction of arterioles, there is a tendency towards a 
gradual diminution in the rate of flow, which appears to be caused by cedema of 
