246 THE ADRENAL SYSTEM AND VASOMOTOR FUNCTIONS. 



renal glands indirectly furnish to the l>lood-plasma accounts for 

 the phenomena witnessed. The abrupt increase in the production 

 of carbonic acid after death is due to the sudden relaxation of the 

 normal tonic vascular contraction incident upon the lethal state 

 and to the equally sudden onslaught of oxidizing principle upon 

 the myosinogen thus induced. Myosinogen becomes myosin after 

 the intrinsic combustion processes have ceased. 



But can functional activity be maintained in an organ 

 merely by an increase of the local blood-supply? That such 

 is the case may be shown by means of one of Claude Bernard's 

 experiments, that in which he demonstrated the existence of 

 vasodilator nerves. Having severed the chorda tympani, a 

 branch of the facial distributed to the submaxillary gland, 

 he found that, when the peripheral segment of the cut nerve 

 that leading to the gland was electrically stimulated, its 

 normal function became manifest. Mathias Duval described 

 the phenomena that immediately ensue as follows: "While the 

 salivary secretion is thus increased, the blood-vessels of the 

 gland are seen to become greatly enlarged; previously invisible 

 arterioles become red and turgescent. If the main trunk of 

 the gland is exposed, it is seen to increase in size, while its 

 contained blood, blackish before the experiment, becomes as red 

 as arterial blood the moment the chorda tympani is stimulated; 

 indeed, if the vein is cut, the blood may be seen to flow in 

 rhythmic jets, as it does from an artery, while it merely drools 

 out when the gland is in the state of rest: i.e., when the 

 chorda tympani is not excited." 



The organ selected for the illustration, the submaxillary 

 gland, is particularly advantageous for the purpose, because 

 its vasodilator nerve, the chorda tympani, is isolated from the 

 vasoconstrictor branch of the sympathetic, also distributed to 

 the gland: a feature of importance. Again, it is evident that 

 function occurs without the active participation of the nerve- 

 impulse per se, such as that associated with a "motor" nerve. 

 We have, in Professor DuvaPs presentation of the process, an 

 exact description of the mechanism of active function. There 

 is not only increase of blood, but increase of energizing blood: 

 i.e., blood that is not allowed to become venous in situ. The 

 carbonic acid evolved must at once be removed; hence the 



