406 



Dr. E. H. Embley. 



[June 13, 



The following table gives some of the results taken from 35 experiments 

 performed in this connection. 



3 — 5 p.c. C 2 H 5 C1 vapour in air inspired. Respiration unaffected. 



4 



» 



33 



93 



„ in 13'. 



i n 



IV 





39 



33 



slowed in 14'. 



TO 



?> 



39 



99 



arrested in 2' 15". Blood- press, at 10 mm. Hg 











from cardiac inhibition. 



xo 



99 



99 



33 



arrested, in o 40 . .blood-press, at 40 mm. Jig 











from cardiac inhibition. 



Id O 





99 



93 



arrested in 8' 10". Blood-press, at 20 mm. Hg 











from cardiac inhibition. 



20 



99 



33 



39 



greatly slowed. Blood-press, at 68 mm. Hg 











from cardiac inhibition. 



20 



99 



39 



99 



arrested in 5' 35". Blood -press, at 56 mm. Hg 











from cardiac inhibition. 



30 



99 



33 



rj 



arrested in 3' 10". Blood-press, at 15 mm. Hg 











from cardiac inhibition. 



30 



93 



93 



39 



greatly slowed in 8' 40". Blood-press, at 











18 mm. Hg from cardiac inhibition. 



30 



39 



33 



99 



arrested in 3' 14". Blood-press, at 











35 - 5 mm. Hg from cardiac inhibition. 



30 



JJ 



33 



39 



arrested in 2' 45". Blood-press, at 50 mm. Hg 











from cardiac inhibition. 



In each 



of 



these experiments 



the 



respiration returned as the blood- 



pressure recovered. 



It was found, as this table shows, that the blood-pressure falls considerably 

 before the respiration stops, which latter recovers when the blood-pressure 

 rises again, as in fig. 10. The correspondence with the effects of chloroform 

 is still closer, since respiration may be paralysed by ethyl chloride inde- 

 pendently of fall of blood-pressure, but not under the ordinary conditions of 

 administration by respiration. It occurs, for instance, when, the liquid ethyl 

 chloride is sprayed into the pharynx, but then only when the vagi are 

 cut or in a state of depressed excitability, otherwise inhibition of the heart 

 would occur and a fall of blood-pressure ensue in consequence. 



There is, however, a type of respiration which seems peculiar to a certain 

 depth of ethyl chloride narcosis. It is found to occur as an antecedent to 

 respiratory failure. It is characterised by a remarkable prolongation of the 

 respiratory pause. The tracing closely resembles that which occurs after 

 division of the vagi in an otherwise normal dog, but with the difference that 

 in this case the vagi are unsevered, as is seen in the blood-pressure tracing, 

 fig. 11, in which the successive respirations occur at the apex of each curve. 

 The blood-pressure falls after each small group of inspirations in consequence 

 of the slowing of the heart rate itself, a result of vagus inhibition. The 

 further accession of ethyl chloride to the blood stream being prevented by 

 the arrest of further respiratory intake, stimulation of the vagus mechanism 



