448 THE DYNAMICS OF CARDIAC ACTION. 



Again, the distribution of the nerve clearly points to the 

 adrenals as the source of the "augmentor phenomena." Pro- 

 fessor Foster states that it "may be traced from the spinal cord 

 by the anterior root of the third spinal nerve, through the 

 ramus communicans to the corresponding splanchnic ganglion 

 (G"') f and thence by the second ganglion (G" ), the annulus 

 of Vieussens, and the ganglion (G'J to the cervical sympathetic 

 (Sy), and so by the vagus trunk to the superior vena cava 

 (S. V. C.)" Indeed, he so accurately traces out, in the an- 

 nexed illustration, what to us appears to be the direct path- 

 way to the adrenals, in the frog, that his own words will serve 

 our purpose: "By watching the effects of stimulating the sym- 

 pathetic nerve at various points of its course we may trace these 

 augmentor fibers from their junction with the vagus down the 

 short sympathetic of the neck, through the first splanchnic or 

 sympathetic ganglion connected with the first spinal nerve ( G r ), 

 through one or both the loops of the annulus of Vieussens, 

 (An. V.), through the second ganglion connected with the 

 spinal nerve (G" ), to the third ganglion connected with the 

 spinal nerve (G'" ), and thence through the ramus communicans, 

 or visceral branch of that ganglion (r. c.), to the third spinal 

 nerve (III), by the anterior root of which they reach the 

 spinal cord." If, in the illustration, as above described, the 

 identity of G'" is noted, i.e., the splanchnic ganglion, the 

 fact that the "augmentor" stimuli follow the course outlined, 

 to the adrenals, will appear. We have already witnessed the 

 effects of lesions of the bulb in causing overactivity of the ad- 

 renals through this nervous path. Especially is it well illus- 

 trated by Claude Bernard's memorable experiment, during 

 which he discovered that puncture of the fourth ventricle gave 

 rise to glycosuria: a condition due, we have seen, to suprarenal 

 overactivity. 



We must not lose sight of the fact, however, that "aug- 

 mentor" phenomena do not only include increase of the force 

 of the heart, attributable, in our opinion, to the adrenal se- 

 cretion, but also increase of the rapidity of the heart-beats. 

 It is evident that if the adrenals were the only sources of 

 energy involved in the process we would obtain increased force 

 and slowing of the heart's action. To what, therefore, can we 



