136 STUDIES IN ADVANCED PHYSIOLOGY. 



When a muscle contracts some of its living muscle sub- 

 stance disintegrates into simpler compounds, and by this 

 disintegration energy is set free which the muscle utilizes, 

 much as in the case of a bit of nitroglycerine. The nitro- 

 glycerine disintegrates into simpler chemical compounds, 

 and by the disintegration a large amount of energy is liber- 

 ated to lift the rock, remove the stump, or what not. A 

 muscle contraction is, therefore, in reality a muscular sub- 

 stance explosion differing from the nitroglycerine analogy, 

 in the fact that there are but particles, here and there, 

 throughout its substance which disintegrate, and not the 

 entire muscle itself. The old view that a muscle contracts 

 because at the time of its contraction something is oxidized 

 is not correct. This may be proved by removing from a 

 muscle all traces of oxygen and then stimulating it. It 

 will contract as usual. Muscles must, however, have 

 nourishment and air carried to them to be built up, to have 

 these wastes repaired, but not to produce the direct con- 

 traction. As for the same reason there would have to be 

 carried to the nitroglycerine factory all the ingredients to 

 make nitroglycerine without any intention whatever of 

 having the explosion occur by doing so. 



Now, muscle substance is mainly albuminous. The 

 question at once arises whether any foods other than albu- 

 mens may serve to nourish the muscles.' That other foods 

 may figure so is argued by the fact that most of our muscu- 

 lar domestic animals are herbivorous; that is, their food 

 consists largely of other than albuminous material. There 

 seems, therefore, a difficulty at first in explaining how 

 foods not albumens, that is, containing no nitrogen, can be 

 built into living muscle substance which is albuminous, that 

 is, which does contain nitrogen. This apparent difficulty 

 is removed, however, at once, by observing that a working 

 muscle seems to retain all the nitrogenous products which 

 have resulted in the muscle disintegration. Or, to be more 

 explicit and to the point, the living muscle albumen disin- 

 tegrates into products which contain the nitrogen and into 



