x THE FORE-BRAIN 571 



that on exciting different points of the cortex there was respira- 

 tory arrest. 



Faradisation of one point of the pre-frontal lobe, that is, of the 

 cortex lying in front of the motor area, also produces arrest of 

 respiration in the inspiratory phase, preceded by acceleration of 

 rhythm (H. Muiik). At other points on the inferior surface of the 

 same lobe it produces arrest of respiration in the expiratory phase, 

 also preceded by acceleration. These effects were obtained not 

 only on dogs but also on monkeys. 



The subsequent work of W. G. Spencer showed that the 

 inspiratory effects obtained on exciting the cortex of the inferior 

 surface of the pre-frontal lobe are apparently connected with the 

 olfactory function. 



Lastly, Langelaan and Beyermann (1903) claimed to have 

 discovered on the dog an area lying at the extremity of the sigmoid 

 gyrus, where the coronary fissure meets the pre-Sylvian, the 

 electrical excitation of which with very weak faradic currents 

 produces respiratory acceleration, followed by inspiratory arrest. 

 On the basis of clinical observations they hold that a similar 

 centre also exists in man at the base of the second frontal convolu- 

 tion near the pre-central gyrus. 



After the discovery of Hitzig and Fritsch, Schiff showed that 

 faradisation of the motor zone may produce cardiac and vascular 

 effects. Many subsequent observers have continued the study of 

 this subject. Danilewsky found that on exciting Hitzig's centre 

 for ocular movements in the curarised dog, blood pressure was 

 raised owing to vaso-constriction and slowing of cardiac rhythm. 

 Bochefontaine, who also operated on curarised dogs, observed that 

 the circulatory effects were obtained from the whole motor area, 

 from a much more extensive surface than was assumed by 

 Danilewsky. These reactions consist in a marked increase of 

 arterial pressure with delay in cardiac rhythm. The pressor 

 effect is sometimes preceded by a depressor effect, the former is 

 probably due to the predominance of vascular spasm, the latter to 

 predominance of cardiac inhibition. 



Eichet found that faradisation of the anterior part of the 

 sigmoid gyrus in particular produced circulatory effects ; a short 

 stimulation sufficed to produce a marked rise of arterial pressure, 

 after a long latent period ; the pressor effect persists for a very 

 long period ; and finally the excitability of the cortex disappears 

 after quite moderate stimulation, every reaction ceasing, even to 

 maximal currents. 



Frangois-Franck and Pitres made a minute analysis of the 

 circulatory reactions to cerebral faradisation. In order to separate 

 the effects on the vessels from those on the heart, they atropinised 

 the animal or cut the vagi. They saw that in operated dogs 

 cortical excitation produced a marked, gradual rise of arterial 



