METHODS OF INVESTIGATION. 
63 
Hoppe-Seyler * quotes the following figures for the composition 
of epidermis and some of the tissues derived from it: 
wey | nes | aun | Aggaot | este 
Carbon......eeeees 50.28 | 50.65 | 61.00 | 51.03 | 51.41 
Hydrogen.......... 6.76 6.36 6.94 6.80 | 6.96 
Nitrogen........0++ 17.21 | 17.14 | 17.51 | 16.24 | 17.46 
OXygen....eccesees 25.01 | 20.85 | 21.75 | 22.51 | 19.49 
Suiphur............| 0.74 5.00 2.80 3.42 | 4.28 
100.00 | 100.00 | 100.00 | 100.00 | 99.55(2) 
flenneberg + obtained the following figures for the composition of 
two samples of pure and dry wool, calculated ash-free: 
I. IT. 
Carbotivigs seventy egies ese eked ee 49.67 49.89 
Hydrogen ........ 06. cece eeee 2.» 7.26 7.36 
Nitrogen...........6665 ase eteteies . 16.01 16.08 
Oxygen. ....e.. scene veces es 23.65 23.10 
Sulphur..............506: ae 3.41 3.57 
100.00 100.00 
The following analyses by Rubner,t Stohmann & Langbein,§ 
and Argutinsky|| show the ultimate composition of ash-free muscular 
tissue after prolonged extraction with ether: { 
ae of 
Hydro- |wit ,| Sulphur, | Oxygen, | Com 
Ber Cont. Pee Cent. Per Cont, Per Cent. Per Cent. perGram, 
als, 
Rubner ..-....-+eeese9- 53.40 16.30 5.6561 
Stohmann and Langbein.| 52.02 | 7.30 | 16.36 24.32 5.6409 
Argutinsky......+++---- 52.33 7.30 16.15 24.22 
* Physiol. Chem., p. 90. 
$ Zeit. f. Biol., 21, 310. 
| Arch. ges. Physiol., 55, 345. 
+ Neue Beitrage, etc., p. 98. 
§Jour. f. prakt. Chem., N. F., 44, 364. 
{It has since been shown by Dornmeyer (Arch. ges. Physiol., 65, 90) 
that such material is not fat-free. 
