4o6 Relation of Acapnia to Shock [April 



diminished, and there was no evidence o£ shock. Beneath the cellu- 

 loid the absence of peristalsis could be observed as well as the effi- 

 ciency of the aeration and failure of the intestines to become dry. 

 The celkiloid was then removed, the intestines spread out, and the 

 aeration continued. After 45 minutes the carbon-dioxide determi- 

 nation indicated a content of 38.8 vol. per cent., and blood-pressure 

 was 1 53 mm. Hg. The intestines were then handled ; in ten minutes 

 blood-pressure had fallen to 98 mm., in twenty minutes to 56 mm. 

 Hg, and in forty minutes there was still 31.6 vol. per cent. of carbon 

 dioxide in the arterial blood. 



In another experiment the intestines were exposed and aerated 

 (not handled). The carbon-dioxide content of the blood was main- 

 tained by connecting a long tube with the trachea. After one hour 

 and a half, blood-pressure had changed but i mm. Hg, and the 

 animal was in good condition. The intestines were then handled 

 and in ten minutes the blood-pressure feil from 122 to 60 mm. Hg. 

 The carbon-dioxide content w^as 45.1 vol. per cent. In twenty-five 

 minutes the blood-pressure was 46 mm. Hg, the carbon-dioxide 

 content normal, and the dog in a severe degree of shock. 



In these abdominal experiments the primary factor concerned is 

 unquestionably the manipulation of the intestines and not any 

 diminution of carbon-dioxide content caused thereby. It will be 

 remembered that in the similar experiments with aeration of the 

 intestines reported by Henderson, the intestines were handled gently. 

 We have been unable to find any mention in his paper of aeration of 

 the abdominal cavity with air alone beneath a celluloid membrane 

 as a control. 



Henderson's control experiment, in which he did not secure 

 shock, included aeration (with astreamof air plus carbon dioxide) 

 of the abdominal cavity beneath a celluloid window in the abdominal 

 wall. Our own experiments show that aeration of the intestines 

 without the addition of carbon dioxide does not produce shock. 



