THE ANALYSIS OF THE ACTION OF THE VAGUS 

 NERVE UPON THE HEART. 



PRELIMINARY NOTICE. 



By Dr. L. J. J. Muskens, Assistant in Physiology, Harvard 



Medical School. 



Presented by H. P. Bowditch, January 12, 1898. 



In a former investigation, carried on in 1895-96 in the laboratory of 

 Prof. Th. W. Engelmann in Utrecht, I was enabled to demonstrate that 

 there exist reflexes from the point of the ventricle upon the centrifugal 

 nerves of the different parts of the heart, the reflex centres being in the 

 medulla oblongata.* These reflexes were for the most part standstills, 

 similar to those produced by striking the intestine of the frog (Reflex of 

 Goltz). In studying these reflexes I found that, during the so called 

 standstills, frequently only the ventricle stops, the auricle meanwhile, or 

 still more frequently a certain part of the sinus, continuing to beat, with 

 perhaps a slight retardation, sometimes even with increased frequency. 

 My research work with Dutch frogs convinced me that this phenomenon 

 must be ascribed to a decreased conducting power. By the influence of 

 the Vagus nerve the passage of the contraction wave over the heart muscle 

 can be blocked. It became clear that the conduction of the peristaltic 

 contraction is a function of the heart, which up to the present time has 

 been too little regarded, especially in the German and French literature 

 on the subject. As to the literature in the English language, there is the 

 admirable work of Gaskell upon the action of the Vagus in the tortoise,t 

 and those of Mc Williams, and of Bayliss and Starling, on the innervation 

 of the mammalian heart. Moreover, the conducting power of the heart 

 has received attention from Engelmann, Wesley Mills, G. N. Stewart, 

 Knoll, Reid Hunt, and Harrington. The surprising fact that, in a sub- 



* Royal Dutch Academy of Sciences, Session of Oct. 26, 1896, and Pfliiger's 

 Archiv., Band LXVII. p. 1-35. 



t Journal of Physiology, Vol. IV, p. 43. 



