358 THE MUSCLE-TISSUE. 



in which uric acid represents the most important end-product of the 

 normal nitrogenous metabolism. In geese it could be demonstrated 

 that after removal of the liver the elimination of lac-tic acid was in 

 no ways influenced by an increased or diminished ingestion of carbo- 

 hydrates, while the administration of larger amounts of albumin 

 invariably results in a corresponding increase of the lactic acid. 

 When from any reason, moreover, albuminous decomposition is in- 

 creased, while the oxidation-processes of the body are at the same 

 time diminished, increased amounts of lactic acid are found in both 

 the blood and the urine. 



We have seen that Siegfried's phosphor-carnic acid gives rise 

 to the formation of lactic acid on hydrolytic decomposition, and it 

 is thus possible that this substance may be its immediate antecedent. 

 Further researches, however, are necessary before the formation of 

 lactic acid from the muscle-albumins can be satisfactorily explained. 

 Whether or not enzymatic influences are here at work we do not 

 know. Salkowski denies this possibility on the basis that lactic acid 

 is not found among the products of autodigestion when perfectly 

 fresh muscle-tissue is allowed to stand in contact with chloroform- 

 water, as the chloroform, according to this observer, does not pre- 

 vent the action of enzymes. If this property holds for all ferments, 

 the conclusion would also follow that the formation of lactic acid 

 can neither be referable to the action of living protoplasm, as the 

 chloroform represents a strong protoplasmatic poison. "We have 

 seen, as a matter of fact, that muscle-plasma also becomes acid after 

 the occurrence of coagulation, and protoplasmatic activity here 

 manifestly does not enter into consideration. We are hence forced 

 to the conclusion that the formation of lactic acid is either referable 

 to the action of a ferment which is destroyed by chloroform, or that 

 it results from a spontaneous decomposition of certain substances 

 which are especially unstable. 



Besides paralactic acid, traces of common lactic acid also are said 

 to occur in muscle-tissue. To isolate the bodies in question, the fol- 

 lowing procedure may be employed. 



Isolation and Quantitative Estimation. A carefully weighed 

 amount of muscle-tissue is finely hashed, repeatedly extracted with 

 cold water, and the mixture passed through a muslin filter. The 

 resulting fluid is feebly acidified with sulphuric acid and boiled, 

 so as to remove the coairulable albumins. Baryta-water is now 

 added so long as a precipitate is formed ; this is filtered off. The 

 filtrate is freed from the barium that was added in excess by pass- 

 ing carbon dioxide into the solution, when it is boiled, filtered, and 

 concentrated to a thin syrup. Care should be taken, however, that 

 the temperature does not exceed 70 C. toward the end. The re- 

 sulting material is treated with ten times its volume of absolute 

 alcohol, set aside for a while, and filtered. 'Flic alcoholic solution is 

 evaporated on a water-bath, and the remaining thick syrup treated 

 with about an equal amount of a moderately dilute solution of phos- 



