312 PROFESSOR E. A. SOHAFER AND DR H. J. SCHARLIEB ON THE 
form, while Htrraie* found evidence of dilatation of these vessels, followed by 
constriction. Newman f observed constriction of pulmonary capillaries in the frog as 
the result of chloroform inhalation. SHERRINGTON and Sowron,{ working with the 
isolated mammalian heart perfused with Ringer’s solution by Langendorff’s method, 
observed a diminished flow of the perfusion fluid when chloroform was added to it; 
this they were inclined to ascribe to a contraction of coronary vessels under its influence. 
C. J. Marrin$ has suggested that this diminution of flow through the coronary 
vessels may be accounted for, without the necessity of assuming constriction of those 
vessels, by the fact that a diminished action of the cardiac musculature, such as chloro- 
form produces, may tend by itself to diminish the rate of circulation through its vessels. 
To this we may add that in a heart which is separated from its surroundings and fed 
by the perfusion of fluid under pressure into the root of the aorta, in which therefore 
the mechanical conditions are very different from those which obtain normally, the 
aortic valves do not necessarily act efficiently, but often permit of some passage of fluid 
into the cavity of the left ventricle, and through this into the left auricle, and so out 
by the cut pulmonary veins; and the extent of this valvular defect with the consequent 
leakage will vary with the condition of tone of the heart and the force of its contractions. 
Opinions on this subject being thus divided, it appeared important in the first 
instance to determine what is precisely the action of chloroform upon the arterial 
system. The method which we have used for this purpose is the classical one of 
perfusing the vessels with blood or saline fluid containing the drug in solution. The 
chloroform used for this purpose and in most of our experiments has been Duncan & 
Flockhart’s, sp.gr. 1°49. The result of our preliminary experiments || showed that a 
solution containing from 1 gramme to 5 grammes of chloroform to the litre of cireu- 
lating fluid produces a marked constriction of the frog’s arterioles, and that this con- 
striction is apparent whether the medulla oblongata and spinal cord are left intact or 
destroyed. These observations established the fact that for high percentages of chloro- 
form (5 grammes per litre is approximately a saturated solution, and 1 gramme per litre 
is therefore one-fifth saturated) there is a pronounced excitation by the drug of the 
musculature of the arterioles—whether operating directly or through the vasomotor 
nerve-endings, our preliminary experiments did not decide—which may contract under 
its influence to such an extent as almost to arrest the flow of circulating fluid. 
Since the publication of these preliminary results, C. J. Marrry,§ in confirmation 
of earlier experiments in conjunction with Empiry,! has made observations upon the 
mammalian kidney by the plethysmographic method which appear to indicate that 
in dilute solution—the actual dosage was not determined, but the perfusing fluid 
(blood) was first passed through the lungs, into which a mixture of air and chloroform 
vapour was pumped—chloroform has the effect upon the blood-vessels ascribed 
* Pfhliiger’s Arch., vol. xliv. p. 596, 1889. + Jour. Anat. and Phys. vol. xiv., 1879, p. 495. 
{ Thompson- Yates Laboratories Reports, 1908, vol. v. § Private communication. 
|| Communication to the Physiol. Soc. ; Jour. Phys., vol. xxix., 1908. 
“I Brit. Med. Jour., April 1902. Lancet, 1902. 
