244 THE ADRENAL SYSTEM AND VASOMOTOR FUNCTIONS. 



of urea is not materially increased during muscular exertion 

 tends to eliminate the proteids. Muscles from which glycogen 

 is absent are stated to respond to stimulus; but the inherent 

 irritability of muscle-tissue readily accounts for this. On the 

 whole, experimental evidence, if considered in the light of the 

 views herein advanced, tends to show that glycogen is the main 

 constituent of myosinogen with which the oxygen of the Hood- 

 plasma combines. 



The absence of free oxygen in muscle has been adduced 

 as evidence to show that the carbonic acid evolved could not 

 be formed by direct combustion. It becomes clear that if the 

 oxygen is used up to the last to such a degree that a muscle 

 will absorb oxygen from the surrounding atmosphere none 

 will be obtained from its tissues, even with the air-pump. 

 The transition of a muscle from its normal neutral reaction to 

 an intensely acid one when the rigor mortis is fully established, 

 is also accounted for by the oxidation of glycogeu. Prolonged 

 tetanus likewise causes acidity of the muscle; we have seen 

 that this is due to excessive suprarenal activity: i.e., to hyper- 

 oxidation. 



This subject is of such importance that we deem it ad- 

 visable to meet each mooted point as presented by Professor 

 Foster precisely as if the problems were placed before us for 

 solution: 



1. "At the outset of rigor mortis there is a very large and 

 sudden increase in the production of carbonic acid: in fact, 

 an outburst, as it were, of that gas." 



The onset of rigor mortis also represents the moment when 

 vascular tonic contractions cease; the blood-vessels being sud- 

 denly dilated, a correspondingly great amount of oxidizing 

 substance is as suddenly brought into contact with the energy- 

 holding substances in the myosinogen, and an outburst of car- 

 bonic acid ensues. 



2. "The increased production of carbonic acid during 

 rigor mortis is not accompanied by a corresponding increase 

 in the consumption of oxygen." 



This conclusion, based on the consumption of oxygen in 

 which the dead experimental animal is placed, does not take 

 into account the oxygen stored in the animals' blood-plasma. 



