TRAUBE-HERING CURVES, 



39 



oscillations, rhythmic variations of tension frequently appear in the 

 tracings of arterial pressure. 



These variations are known as Traube-Hering curves. 1 They can be 

 evoked with the greatest ease by the injection of a little magnesium 

 sulphate solution into the circulation of the dog (Fig. 84). During the 

 asphyxial rise of arterial pressure in the curarised dog, these curves are 

 of constant occurrence, and also after injection of a large dose of 



FIG. Si. Traube-Hering curves produced by injection of magnesium sulphate ; dog.- Hill. 



morphia. In conditions of anaemia of the bulbar centres, produced 

 either by tying the cerebral arteries or compression of the brain, or 

 after injection of chloroform into the cerebral arteries, Traube curves 

 frequently become apparent. Very often these oscillations of arterial 

 pressure are accompanied by a periodicity of the respiration, which is 

 known as Cheyne-Stokes breathing. Tt would appear as if each oscilla- 

 tory rise of arterial 

 pressure excited the 

 respiratory centre, 

 and evoked a group 

 of respirations. 2 



These oscillations 

 of arterial pressure 

 are produced by 

 periodic constriction 

 and dilatation of vas- 

 cular areas. On 

 recording the volume 

 of the kidney, this 

 organ is found to con- 

 tract when the arte- 

 rial tension rises. 3 



They are usually 

 to be ascribed to a 

 periodical excitement 

 of the vasomotor centre. A deficient circulation through the bulb 

 excites the centre, the arterial pressure in consequence rises, the rise of 

 pressure flushes the bulbar centres with more blood, the centres then 

 cease to be excited, the pressure falls again, and the cycle of events is 

 repeated. Traube curves may in some cases be peripheral, and not 

 central, in origin. 



By the injection of essential oil of absinthe in a curarised animal, the 

 vasomotor centre can be excited to the discharge of a succession of powerful 



1 Traube, Centralbl. f. d. med. Wissensch., Berlin, 1865, S. 882 ; Hering, Sitzungsb. d. 

 k. Akad. d. Wissensch., Wien, 1869, Bd. Ix. S. 839. 



2 Hill, "Phys. and Path. Cerebral Circulation," London, 1896, p. 130 et seq. 



3 Eoy, Journ. PhysioL, Cambridge and London, 1882, vol. iii. p. 217 et seq. 



FIG. 85. Plethysmographic tracing of arm and record of 

 Cheyne-Stokes respiration ; man. Hill. 



