PRODUCTS OF MUSCULAR WASTE. 447 



nets of oxidation, which are eventually to find their way into the urinary 

 secretion, or to escape by the respiratory surfaces. It is immaterial what 

 the first aspect of these substances may be, creatine, urea, extractive, etc. ; 

 this much is absolutely certain, that they are on the downward career, 

 and will end as urea, sulphuric, carbonic acids, etc. The experiments 

 both of Reymond and Liebig prove that the muscles, when at Products of 

 rest, contain no acid juice, and during their activity it is known muscular 

 that the degree of acidity is proportional to the energy with * 

 which they have been contracting. It can not for a moment be sup- 

 posed that this acidity is the cause of the contraction ; on the contrary, 

 it is its result. 



Among the products arising during muscular action may be more par- 

 ticularly mentioned inosite, or muscle sugar, which is isomeric inosite and 

 with glucose, and creatine, which, though it contains so large creatine - 

 a proportion of nitrogen, must be regarded as a product of the waste go- 

 ing on. By the loss of two atoms of the element of water, it gives origin 

 to creatinine, which is accordingly found in the muscle juice, the blood, 

 and the urine. Indeed, these two substances seem to be inversely pro- 

 portional to each other. 



The partial oxidation which has given rise to these various products 

 can not occur without an elevation of temperature. A second stage of 

 the process of muscular action consists in the removal of the heat and 

 of the partially oxidized bodies. 



We have only to look at the minute anatomy of the parts under con- 

 sideration to recognize the manner in which this double re- Removal of the 

 moval is accomplished. The arterial capillaries, when they ^zed^dies by 

 break up for their final distribution, run parallel with the the blood. 

 muscular fibres, as also do the attendant veins. From one to the other, 

 at short intervals, as seen in Fig. 227, intercommunicating vessels trans- 

 versely pass, the whole being arranged on such a system as to afford 

 the readiest means of removal of the blood as fast as it becomes venous 

 a facility of removal of the last importance for carrying off the wasted 

 products of oxidation ; and in this manner, those products, whatever they 

 may in the first instance be, find a ready means of escape, and so the 

 muscular fibre by degrees is relieved from these results of functional ac- 

 tivity. 



As for the heat which has arisen in a secondary way from the meta- 

 morphosis which has been going on in the fibre, that is in like manner 

 extracted. It is difficult to conceive of a more effective method by which 

 the heat could be taken away from the wasted fibre, or indeed we might 

 say from the interior of the whole mass of the muscle. The current of 

 vendus blood bears away with it not only the products that have arisen 

 in the oxidation, but likewise the heat. 



