TRANSACTIONS OF SECTION I. 629 
The question of the value of adrenalin as a restorative to the circulatory 
system will be incidentally discussed in the body of the paper. 
I have performed in all more than eighty experiments—two on cats and 
the rest on dogs. Chloroform, ether, or the A.C.E. mixture were the 
anesthetics used. In some few cases curari has been used in addition. The 
blood-pressure has been taken from the carotid artery, and the injections 
made into the saphenous or femoral vein. A glass plethysmograph was 
used for recording changes in the voiume of the limb, and for similar 
changes in the intestinal wall an air oncometer was used, each of these 
being connected with a piston recorder. The method described by Oliver 
and Schafer * was employed for recording the effects upon the heart. A 
hook is caught in the epicardium of the auricle, and another in the 
ventricle. From these threads pass over pulleys moving on a horizontal 
axis; the threads then pass vertically downwards to be attached to long 
elastic levers of steel. To the ends of the levers writing points are 
attached. 
Physiological Effects. 
One of the most familiar, and at the same time most striking, actions 
of atropine is paralysis of the peripheral terminations of the vagus in 
the heart. It would naturally be expected that this effect, like section of 
the vagi, since it cuts off the tonic inhibitory influence of the nerve centre, 
would exercise an augmentory effect upon the heart and raise the blood- 
pressure. This is, in fact, usually stated to be the case (see Dixon,” 
Schmiedeberg,* and Sollmann*). But my own experiments furnish no 
evidence of any action whatever on the vasomotor system. I have been 
unable to find any original papers giving details of experiments upon 
animals, with tracings of blood-pressure.° 
In my series of more than eighty experiments on dogs, I have never 
observed any rise in blood-pressure upon the injection of atropine into the 
circulation.® 
This applies to the allied drugs mentioned in the introduction. The 
drugs have been tested under very varying conditions as to dosage, amount 
of fluid injected, temperature of fluid injected, and rate of injection. In- 
all cases, when any effect whatever has been produced, this has been in 
the direction of a fall of blood-pressure. In small doses this is slight and 
transient ;" in large doses marked and long continued—sometimes for an 
hour. In some cases, however, even after large doses, recovery is fairly 
rapid.« 
Pra many cases, it is true, the tracings show a slight preliminary rise of 
blood-pressure. This, generally followed by a much more pronounced and 
significant fall, is, I have convinced myself, simply due to the injection 
1 Jour. of Physiol., vol. xviii. p. 256, 1895. 
2 Dixon, Manual of Pharmacology, London, 1906. 
3 Op. cit. 
A golinanik Text Book of Pharmacology, Philadelphia, 1906. 
5 The literature, however, to which I have access is limited. : 
6 Professor Vincent informs me that so far as his memory serves him he 
has never seen a rise of blood-pressure on the administration of atropine. 
7 A possible criticism of my results would be that doses small enough had 
not been tried, and that the initial increased rate of heart beat and concomitant 
rise in blood-pressure, whether due to this or to vaso constriction, had been 
overlooked. Every precaution has been taken to avoid this error. No dose, 
however small, has in my dogs produced the slightest rise in blood-pressure. 
In many cases so small was the amount of drug injected that no effect whatever 
was produced other than that due to the fluid administered, which point has 
been very frequently tested by control injections of the same quantity of normal 
saline solution. : 
