THE OXIDIZING SUBSTANCE AND MYOSINOGEN. 245 



As shown in the first answer, the oxidizing substance in the 

 latter is fully able to give rise to the production of the car- 

 bonic acid observed. 



3. "A muscle (of a frog, for instance) contains in itself 

 no free or loosely attached oxygen; when subjected to the 

 action of a mercurial air-pump it gives off no oxygen to a 

 vacuum, offering, in this respect, a marked contrast to blood." 



A detached muscle is, as far as its vascular elements arc 

 concerned, similar to a muscle in which rigor mortis has begun. 

 Its oxygen is not in sufficiently loose combination to yield to 

 the dissociating action of the pump when stored in myosinogen, 

 owing to its affinity for various constituents of the latter. 

 While in extra corpore blood the oxidizing principle of the 

 plasma might yield its oxygen in vacuo, it is probable that it 

 will not, judging from recorded data, though it will do so to 

 salicylic aldehyde, benzol, and benzilic alcohol, as shown by 

 Schmiedeberg, Jaquet, Salkowsky, Abelous and Biarnes. 



4. "When placed in an atmosphere free from oxygen it 

 will not only continue to give off carbonic acid while it remains 

 alive, but will also exhibit at the onset of rigor mortis the same 

 increased production of carbonic acid that is shown by a mus- 

 cle placed in an atmosphere containing oxygen. It is obvious 

 in such a case that carbonic acid does not arise from the direct 

 oxidation of the muscle-substance, for there is no oxygen 

 present at the time to carry on oxidation." 



The oxidizing substance when brought into contact with 

 the myosinogen gives rise to an intramuscular reaction: one 

 which, therefore, may continue in any atmosphere whether 

 the latter contain oxygen or not. 



Professor Foster then summarizes prevailing views as to 

 this subdivision of the general subject, as follows: "We are 

 driven to suppose that during rigor mortis, some complex body 

 containing in itself ready-formed carbonic acid, so to speak, 

 is split up, and thus carbonic acid is set free, the process of 

 oxidation by which that carbonic acid was formed out of the 

 carbon-holding constituents of the muscle having taken place 

 at some anterior date." 



The process appears to us to be fully accounted for as 

 follows: The presence of the oxidizing principle which the supra- 



