402 PATHOLOGY AND TEEATMENT OF SHOCK AND SYNCOPE. 



ence of a sudden and violent injury to nerves over the activity 

 of the heart." The experiments of Goltz show that this defini- 

 tion is perfectly correct, but you must not forget that there are 

 the two factors in shock as seen in the frog. First, the stoppage 



Fia. 152. — Diagram to illustrate the Effects of the Horizontal and Vertical 

 Positions on the Circulation of the Frog in Shock. 



a. Normal circulation in the upright position, h. Circulation after dilatation of 

 the veins has been produced by a blow on the intestines. The blood does 

 not reach the heart, and it beats empty, so that the circulation stops, 

 c shows the circulation in a horizontal position after the veins have been 

 dilated, as in h. The veins are still dilated, but the blood reaches the heart, 

 and the circulation is carried on. Fig. c is perhaps too diagrammatic, as i: 

 appears to show an empty space in the veins. In reality the veins, being 

 very thin-walled, collapse. Fig. h is open to the same objection, but if we 

 suppose ourselves to be looking at the vein from the front instead of in 

 section, h represents almost exactly what I have seen myself in repeating 

 Goltz's experiment. This diagram was not in the original paper, but is 

 taken from my Text-Booh of Pharmacology^ &c. 



of the heart ; and second, dilatation of the vessels. These are 

 quite distinct, and I have frequently observed that Mows of 

 moderate severity vjill produce in some frogs stoppage of the heart 

 vAthout dilatation of the vessels, in others vascular dilatation 

 without arrest of the cardiac pulsations, although severe Mows 

 generally produce both.* 



The pallor of the surface and the coldness of the skin are the 

 next symptoms which engage our attention, and what we have 

 just learned regarding the circulation will render their explana- 

 tion easy. The rosy flush of health is due simply to the red 

 colour of the blood shining through the skin as it courses 

 through the capillaries, and whenever the circulation is stopped, 

 either by the vessels contracting as after exposure to cold, or by 

 the blood stagnating in the abdomen as in shock, pallor over- 

 spreads the surface. The warmth of the external parts of the 

 body is due to the warm blood from the interior, which heats 

 * Eesults of a series of unpublished experiments. — T. L. B. 



