GLYCOGEN, MUSCLE SUGAR, LACTIC ACIDS. 553 



Glycogen is a constant constituent of the living muscle, while it may 

 be absent in the dead muscle. The quantity of glycogen varies in the 

 different muscles of the same animal. BOHM found 10 p. m. glycogen 

 in the muscles of cats, and moreover he found a smaller amount in the 

 muscles of the extremities than in those of the rump. MOSCATI found an 

 average of 4 p. m. in human muscles, and SCHONDORFF 1 has found a max- 

 imum of 37.2 p. m. in the dog-muscle. Reports as to -the quantity of 

 glycogen in the heart are conflicting; although the heart is considered 

 as somewhat poorer in glycogen than the other muscles, still this dif- 

 ference is not very great, and can be explained by the ready disappearance 

 of glycogen from the heart after death, as well as after starvation and 

 after strong work (BORUTTAU, JENSEN 2 ). Work and food have a great 

 influence upon the quantity of glycogen. BOHM found 1-4 p. m. 

 glycogen in the muscles of fasting animals, and 7-10 p.m. after partak- 

 ing of food. As stated in Chapter VIII, work, starvation, and lack of 

 carbohydrates in the food cause the glycogen to disappear, earlier, from 

 the liver than from the muscles. 



The sugar of the muscles, of which only traces occur in the living muscle, 

 and which is probably formed after the death of the muscle from the 

 muscle-glycogen, is, according to the investigations of PANORMOFF, 

 in part dextrose, but consists chiefly of maltose (OSBORNE and ZOBEL 3 ) 

 with some dextrin. 



Lactic Acids. Of the oxypropionic acids with the formula C 3 H 6 O3 

 there is one, ethylene lactic acid, CH 2 (OH).CH 2 .COOH, which is not found 

 in the animal body, and therefore has no physiological chemical interest. 



CH 3 

 Indeed only a-oxypropionic acid or ethylidene lactic acid, CH(OH),.of 



COOH 



which there are three physical isomers, is of importance. These three 

 ethylidene lactic acids are the ordinary, optically inactive FERMENTA- 

 TION LACTIC ACID, the dextrorotatory PARALACTIC or SARCOLACTIC ACID, 

 and the LEVOLACTIC ACID obtained by SCHARDINGER by the fermenta- 

 tion of cane-sugar by means of a special bacillus. This levolactic acid, 

 which has also been detected by BLACHSTEIN in the culture of GAFFKY'S 

 typhoid bacillus in a solution of sugar and peptone, and which is formed 

 by various vibriones, need not be described here. 4 



1 Bohm, Pfliiger's Arch., 23, 44; Schondorff, ibid., 99; Moscati, Hofmeister's 

 Beit rage, 10. 



2 Boruttau, Zeitschr. f. physiol. Chem., 18; Jensen, ibid., 35. 



3 Panormoff, Zeitschr. f. physiol. Chem., 17; Osborne and Zobel, Journ. of Physiol., 

 29. 



4 See Schardinger, Monatshefte f. Chem., 11; Blachstein, Arch, des sciences biol. 

 de St. Petersbourg, 1, 199; Kuprianow, Arch. f. Hygiene, 19, and Gosio, ibid., 21; 

 Herzog and Horth, Zeitschr. f. physiol. Chem., 60. 



