470 AN AMERICAN TEXT-BOOK OF PHYSIOLOGY. 



in the minute was produced, together with increase of blood-pressure, from 

 vaso-constrictor action. The experiments are dangerous. 



Peripheral Reflex Centres. It is now much discussed whether the periph- 

 eral ganglia can act as centres of reflex action. According to Franck 1 the excita- 

 tion of the central stump of the divided left anterior limb of the annulus of 

 Vieussens is transformed within the first thoracic ganglion, isolated from the 

 spinal cord by section of its ramus communicans, into a motor impulse trans- 

 mitted by the posterior limb of the annulus. This motor impulse causes, inde- 

 pendently of the bulbo-spinal centres, a reflex augmentation in the action of the 

 heart, and a reflex constriction of the vessels in the external ear, the submaxil- 

 lary gland, and the nasal mucous membrane. This experiment, in conjunction 

 with the facts in favor of other sympathetic ganglia acting as reflex centres, 2 

 seems to demonstrate that some afferent impulses are transformed in the sym- 

 pathetic cardiac ganglia into efferent impulses modifying the action of the 

 heart. If this conclusion is confirmed by future investigations it will pro- 

 foundly modify the views now entertained regarding the innervation of the 

 heart. 



Intra- ventricular Centre. Kronecker and Schmey, 3 finding that puncture 

 of the inter-ventricular septum at the junction of the upper and middle thirds 

 often caused arrest of the heart with fibrillary contractions, have set up the 

 hypothesis of a co-ordinating centre at that point, essential to the co-ordinated 

 contractions of the ventricle. Their results are possibly due to inhibition ; 4 cer- 

 tainly they are not to be explained by the destruction of a co-ordinating centre. 

 The anatomical basis for such a conception is wanting, careful search having 

 failed to reveal any ganglion-cells in the locality in question, 5 and the heart has 

 been observed to beat for hours and even days after the cardiac tissue of this 

 part of the septum had been destroyed by infarction, caused by the ligation of 

 its nutrient arteries. 6 



The experiments of Stannius, published in 1852, have been the starting- 

 point of a very great number of researches on the innervation of the frog's 

 heart. Stannius observed, among other facts, that the heart remained for a 

 time arrested in diastole when a ligature was tied about the heart precisely at 

 the junction of the sinus venosus with the right auricle. No sufficient 

 explanation of this result has yet been given, nor is one likely to be found 

 until the innervation of the heart is better understood. Stannius 7 further 



1 Franck, 1894, p. 721. 



2 See Wertheimer, 1890, p. 519; Skabitschewsky, 1891, p. 156; Langley and Anderson, 

 1893, p. 435. 



3 Kronecker and Schmey, 1884, p. 89 ; S^e and Gley, 1887, p. 827 ; the latter could not get 

 arrest in 11 out of 14 dogs. 



4 Knoll, 1894, p. 312, observed fibrillation of the auricles in consequence of vagus stimula- 

 tion ; escape of current into the heart was guarded against. 



s Krehl and Romberg, 1892, p. 54. 



6 Porter, 1893, p. 366 ; for the effect of wounds of the heart upon its rhythm, see Rodet 

 and Nicolas, 1896, p. 167. 



* A review of the Stannius literature is given by Tigerstedt, Physiologie des Krcislaufes, 

 1893, p. 196. 



