GOLTZ'S EXPERIMENTS. 40 1 



of these two causes is the true one, or whether they do not 

 both share in the production of shock, if we had not experi- 

 ments on the lower animals to give us some clue to the true 

 solution. Several years ago Professor Goltz, now of Strassburg, 

 found that on striking the abdomen of a frog several times 

 the heart stopped altogether.* After a short pause it again 

 went on, but instead of becoming completely full during each 

 diastole, and sending a large volume of blood into the arteries 

 at each systole, it remained pale and empty; no blood at all, 

 or hardly any, flowed into it during the diastole, and conse- 

 quently it could not send any into the vessels when it did 

 contract, and it might just as well have remained motionless. 

 On looking for the blood that ought to have been supplying 

 the heart, he found that it was stagnating in the vessels of the 

 abdomen, and especially in the veins. The intestinal vessels 

 are so capacious that when they are fully dilated they can 

 hold all the blood in the body. Normally, however, they are 

 kept in a state of partial contraction by the influence of the 

 vaso-motor nerves wliich supply them. It used to be supposed 

 that these nerves only went to the arteries, and that these alone 

 were capable of contraction and relaxation, but Goltz found 

 that the veins also were supplied by vaso-motor nerves, and 

 that they too could contract and dilate, though to a less extent 

 than the arteries. Whenever the power of the vaso-motor 

 nerves w\as destroyed, both arteries and veins dilated and held 

 so much blood that there was not sufficient left to keep up the 

 circulation in the rest of the body. If the frog w'as held in the 

 upright position no blood at all reached the heart, but if it was 

 laid horizontally a little blood trickled into the heart, and the 

 circulation w^as thus kept up, though very weakly. 



Here, then, we have in the frog the same efiects produced by 

 a blow on the abdomen as in the case of the young man who 

 was struck by the carriage pole, with this difference, that in the 

 man we could only feel the weakness of the pulse, while in the 

 frog we can see why it is weak. Professor Fischer says that 

 the best and shortest definition of shock wdiich has yet been 

 oiyen is that of Mr. Savory : — " Shock is the paralysing influ- 



* Virchoid's Archiv, toI. ixvi, 1863, p. 11, and vol. xxix, 1864, p. 394. 



2 D 



