398 



Dr. E. H. Embley. 



[June 13, 



of the dog at the commencement of the experiment. The animal was 

 curarised. Simultaneous records of arterial pressure and bowel volume were 

 taken. 



Fig. 6, showing bowel volume (B.V.) and blood-pressure (B.P.), demonstrates 

 the effect of blood saturated with air containing 30 per cent, of ethyl 

 chloride vapour delivered to the brain for 19, 23, and 13 seconds in the 

 first, second, and third delivery respectively. The first effect produced is 

 vaso-constriction as shown by the simultaneous rise in blood-pressure and 

 diminution in bowel volume. After 4' 15" the second delivery was made, 

 but the effect produced, although under the same conditions, was the very 

 reverse of the first, for the blood- pressure fell simultaneously with the 



Opressure O pressure 



' i 1 — i n 



on off on- off on off 



Fig. 6. — Jr size of original. 



occurrence of an increase in the size of the bowel volume. The third 

 delivery, again under the same conditions, produced effects similar to the 

 second. These latter were obviously vaso-dilator effects. 



Further experiments with the same dog produced combinations of these 

 results. At one time vaso-constriction was followed by vaso-dilation in the 

 one delivery. At another delivery vaso-constriction was followed by vaso- 

 dilation, and then by vaso-constriction. In the last experiments the 

 artificial circulation was continued for as long as 40" — much longer than in 

 the former. In similar experiments upon other dogs the constrictor effects « 

 were more marked and more prolonged. When lower percentages were used 

 the same results ensued, and the effect was roughly proportional to the 

 concentration of ethyl chloride in the blood injected. 



