igoo- 



Observations on Blood Pressure. 



213 



Tracing 27. In this animal double pneumo-thorax had been 

 produced in the manner described with very free openings through the 

 parietes. The whole tracing is too long to reproduce here, but the 



Tracing XXVH. — 3/1 1. — Double pneumothorax previously produced with very free openings through 

 parietes. Pressure well maintained until respiration stopped at 22. Pressure then fell with slow pulse — 

 asphyxia. 



pressure was well maintained until respiration stopped at 22. Then it 

 fell and the pulse became very slow and ceased a couple of minutes 

 later. 



A momentary rise will be noticed at 22 just after the respiration 

 ceased. 



In Tracing 28, on the other hand in which both pleurae had been 

 freely opened, a marked respiratory wave appeared with some rise in 

 pressure when the trachea was clamped at 22. At 23 the attempts at 



Tracing XXVIII. — 3/1 1. — Double pneumothorax previously produced. 22 Trachea clamped. 23 

 Efforts at breathing ceased and then arterial pressure fell. 



respiration stopped, and then the pressure fell slowly with marked 

 slowing of the pulse. About three minutes later the pulse became fast 

 and the pressure rose a few mms., giving a good example of delirium 

 cordis. 



Thus it may be seen that very different tracings are got in 

 different conditions of asphyxia, and that no one description will suffice 

 for every form. This probably is the reason why Lieut.-Col. Lawrie and 

 his critics got so far apart in their statements, some asserting that the 

 pressure fell in asphyxia, and others that it rose, e.g:, Dr. J. H. Potter 



