68 



LECTURE IV. 



began to move about, Bernard noticed that the glycogen disappeared. 

 He furthermore observed that when the muscular tissues of well-nourished 

 mammals or birds were at rest whether voluntarily so or as a result of 

 artificially severing the nerves in them the glycogen content gradually 

 increased, only to disappear again when the muscles were set at work. 



Direct experiments were carried out by S. Weiss. 1 He compared the 

 glycogen content of a frog's hind legs of which one had been tetanized 

 almost to exhaustion while the other was under control and rested. The 

 glycogen in the active muscles decreased from 24.27 to 50.43 per cent. 

 Finally Th. Chandelon 2 has carried out the following experiment : In a 

 rabbit he severed the sciatic and crural nerves, and at the end of from 2 

 to 5 days found in the paralyzed muscles an increase in glycogen amount- 

 ing to from 5.51 to 172.4 per cent. Similarly Marcuse 3 made similar 

 observations, and found the following glycogen values: 



Finally, the same result has been obtained by Edward Kiilz 4 in another 

 way. He caused a well-nourished dog to draw a heavy cart. The animal 

 weighed 45.500 kilograms, and was made to drag the cart for 9 hours 

 and 40 minutes. The dog was then bled to death. The glycogen deter- 

 mination showed the presence of 52.053 grams, i.e., 1.16 grams per kilogram 

 of the dog's weight. A well-nourished dog that is not tired shows a 

 glycogen content of 38 grams per kilogram. For comparison, it may be 

 mentioned that after 28 days of starvation a dog of about the same size as 

 the above-mentioned showed but 1.5 grams of glycogen per kilogram. It 

 is evident, therefore, that after about 9 hours of labor the glycogen stores 

 were consumed to fully as great an extent as in the case of a dog starved 

 for 28 days. Kiilz then repeated the experiment with three other dogs and 

 with the same result. 



A further confirmation of the fact that the carbohydrates serve as an 

 important source of muscular energy is shown by the interesting experi- 



1 Sitzber. Akad. Wiss. Wien. 64, Abt. 1. 



2 Pfliiger's Arch. 13, 626 (1876). 



8 Pfliiger's Arch. 39, 425 (1886). See also Edward Manche", Z. Biol. 25, 163 (1889). 

 4 Beitrage zur Kenntniss des Glykogens, p. 41 (1891), 



