A STUDY OF FEVER. 31 



hereafter drawn from the experiments of Tscheschichiii and 

 myself. 



Having now given 3'ou the experimental facts, it is proper to 

 enter finally upon their discussion, and I shall take up first the 

 subject of the position of the vaso-motor centres. 



In a number of experiments,* which I have performed, galvani- 

 zation of a nerve after section of a cord in the lower cervical 

 region has failed to affect the circulation, or in other words, to 

 influence the vaso-motor centres. To-day we have seen that after 

 separation of the medulla from the pons nerve irritation does 

 influence the circulation. Evidently then the vaso-motor centre 

 is in the medulla. As already'- stated this conclusion is in accord 

 with that of previous observers. 



It is true that Prof. Cyon {Melanges Biologiques tiren du 

 Bulletin de V Acadeniie Imperiale des Sciences de St. Peters- 

 hourg^ t. vii.) found that when the cerebral hemispheres are 

 removed, leaving only the medulla oblongata and the cere- 

 bellum, irritation of a sensitive nerve is not followed by a rise 

 of arterial pressure. The shock and the bleeding from such 

 an operation are, liowever, so great that the results of the 

 experiments are of little value; certainly the loss of blood and 

 nervous disturbance might of themselves very conceivably 

 utterly paralyze the vaso-motor centres, supposing them to be 

 in the medulla oblongata. Therefore it cannot be allowed that 

 the experiments of Prof. Cyon really contradict those about to 

 be cited, which are in accord with those which I have myself 

 performed. 



Dr. C. Dittraarf (Berichte uher die Verhandlugen der Kbnigl. 

 Sachs, Oesellscha/t der Wissenschaften zu Leipzig. Math. 



* See as an example Experiment XXVIII. in an " Investigation into 

 the Action of Veratrura Yiride upon the Circulation," Phila. Medical 

 Times, vol. iv., also pamphlet reprint, 



t Von Bezold may have ascertained the same experimental fact in his 

 Untersuchungen liber die Innervation des Herzens, Leipzig, 1863, but I 

 have never seen his memoir. 



