THE INNERVATION OP THE HEART. 449 



ascribe the quickening of the heart-beats to which stimulation 

 of the augmentor fibers give rise? The answer is easily found 

 in the fact that the vagus fulfills in the heart the same functions 

 it does in other organs: i.e., it incites and governs the active 

 stage of its functional processes. Its prerogatives as governing 

 agency obviously include quickening, as well as slowing, of the 

 heart-beats, the former being the result, as previously stated, of 

 a more rapid vibratory rhythm, while the slowing results from 

 a slower rhythm of the impulses transmitted from the vagal 

 centers. When, therefore, stimulation of the adrenals is in- 

 duced through the augmentor fibers, the vagal centers are cor- 

 respondingly stimulated, owing to the unusual activity of the 

 oxidation processes which the increase of oxidizing substance 

 in the blood engenders, and the frequency of the heart-beats 

 is augmented in proportion. While the adrenal secretion there- 

 fore increases the power of the cardiac pulsations, the vagus 

 increases their number. 



We wish to particularly emphasize this combined action 

 of the adrenals and the vagus, since it represents the functional 

 mechanism that underlies the production of fever. 



That the first effect of stimulation of the augmentor fibers 

 is produced upon the adrenals, the vagal effects being secondary, 

 is strikingly emphasized by the following remark of Professor 

 Foster's in reference to "augmentor" phenomena: "In contrast 

 with the case of the vagus fibers, a somewhat stronger stimula- 

 tion is required to produce an effect; the time required for the 

 maximum effect to be produced is also remarkably long." 



On the whole, it seems to us quite evident that stimulation 

 of the "augmentor" fibers increases the rapidity and the force of 

 the heart-beat by increasing the functional activity of the adrenals 

 and, as a result of the increased oxidation processes thus obtained, 

 that of the vagal centers. The excess of adrenal secretion increases 

 the force of the heart-beats, while the overactivity of the vagal cen- 

 ters increases their number. 



"INHIBITOR" PHENOMENA. We have previously stated 

 that we had not found, in the course of the inquiry to which 

 this work is devoted, the need of a subsidiary function such as 

 that generally understood by the word "inhibition": i.e., arrest, 

 partial or total (by a direct action upon tissues or by interfer- 



