182 ACTION OF NITKITE OF AMYL ON THE CIRCULATION, ETC. 



experiments were made after previous division of the cord in 

 the neck so that the vessels should become relaxed, and the 

 difference produced in their calibre by the vapour being thus less. 

 The results obtained were, as shown in figs. 110, 111 and 112 



Fig. 111. 



Cord cut in the neck. 

 In the last four observations the aorta was compressed ; at o the aorta was 

 opened. — Inhalation begun. + Inhalation stopped. 



th-at sometimes a rise took place during the inhalation, but 

 generally a sinking, much less, however, than in the normal 

 condition. 



We may therefore conclude that the diminution in the blood- 

 pressure is not due to weakening of the heart's action, but to a 



