LACTIC ACID FORMATION IN ACTIVE MUSCLES. 593 



activity to an acid reaction (Du BOIS-REYMOND and others), and the 

 acid reaction increases, to a certain point, with the work. The quickly 

 contracting pale muscles produce, according to GLEISS/ more acid dur- 

 ing activity than the more slowly contracting red muscles. Numerous 

 investigations have been carried out on the cause of this increased acid 

 reaction, using the muscles in situ and also upon removed muscles and 

 rather contradictory results have been obtained. Some have found a 

 diminution in the amount of lactic acid in the active muscle while others 

 have found an increase. 2 The work of FLETCHER and HOPKINS 3 is of 

 great importance in this disputed question, in which they show that in 

 the removal of the muscle, and in its preparation for the testing for lactic 

 acid several sources of error are possible. The mechanical irritation 

 as well as warming or treating the muscle with alcohol (not ice-cold) 

 can lead to a formation of lactic acid. It was also shown that the 

 absence of oxygen accelerated the formation or accumulation of lactic 

 acid, while an abundance of oxygen had the opposite effect. 



It is evident that the experiments with the muscles in situ in other 

 words, with muscles through which blood is passing cannot yield any 

 conclusion to the above question, as the lactic acid formed during work 

 may perhaps be removed by the blood. The following objections can 

 be made against those experiments in which lactic acid has been found, 

 after moderate work, in the blood or the urine, as also especially against 

 the experiments with removed active muscles, namely, that in these cases 

 the supply of oxygen to the muscles was not sufficient, and that the 

 lactic acid formed thereby is not, in accordance with the views of HOPPE- 

 SEYLER, a perfectly normal process. The same is probably true also for 

 the formation of lactic acid with excessive work during life, and ZILLESSEN 4 

 has found that the artificial cutting off of the oxygen supply in the 

 muscles during life, that more lactic acid was formed than under normal 

 conditions. Other observations indicate a formation of lactic acid dur- 

 ing activity. Thus SPIRO and recently also H. FRIES S found an increase 

 in the quantity of lactic acid in the blood during work. COLAS ANTI 

 and MOSCATELLI found small quantities of lactic acid in human urine 

 after strenuous marches, and WERTHER 6 observed an abundance of lactic 

 acid in the urine of frogs after tetanization. 



iPfliiger'sArch., 41. 



* Astaschewsky, Zeitschr. f. physiol. Chem., 4; Warren, Pfliiger's Arch., 24, 

 Monari, Maly's Jahresber., 19; Heffter, Arch. f. exp. Path. u. Pharm., 31; Marcuse, 

 1. c.; Werther, Pfliiger's Arch., 46; Spiro, Zeitschr. f. physiol. Chem., 1; Colasanti. 



3 Journ. of Physiol., 35. 



4 Hoppe-Seyler, 1. c. and Zeitschr. f. physiol. Chem., 19, 476; Zillessen, ibid., 15. 

 6 Spiro, Zeitschr. f. physiol. Chem. 1; Fries, Bioch. Zeitschr., 35. 



6 Colasanti and Moscatelli; Maly's Jahresb.. 17, 212; Werther, Pfliiger's Arch., 46. 



