The Measurement of Arterial Pressure in Man. 529 



A. Compression of both artery and tissue schema (fig. 12). The pressure 

 first rose and the pulse amplitude diminished owing to the shrinkage of the 



Off. Fig. 12. On. 

 tissue schema, and the greater resistance thus developed in it, and higher 

 diastolic pressure consequent in the artery. Then a fall of pressure accom- 

 panied by maximal pulses resulted owing to the artery flattening during 

 diastole. Finally the artery shut up and the pulse ceased to reach the mano- 

 meter. On taking off the compression the pressure and outflow did not return 

 to their previous amounts until the shrunken tissue schema had expanded. 



B. The compression tube leading to the tissue schema chamber was closed. 

 On compressing the artery it began to flatten, and gave maximal swings, and 

 then shut up. No rise of pressure occurred as in " A," because the tissue 

 schema was not compressed (fig. 13). 



Off. Fig. 13. On. 



C. The compression tube leading to the artery chamber was closed 

 (fig. 14). On compressing the tissue schema the pressure rose and the pulse 



Off. On. 

 Fig. 14. 



