THE ALBUMINOIDS. 
73 
The following are some elementary analyses that have been made of 
keral in from different sources : — 
Tissue . 
From Hair. 
Nail. 
Neurokeratin. 
Horn. 
Analyst 
V. Laar.J 
Mulder.2 
Kiihne. 3 
HorbaczewskM 
c 
50*60 
51-00 
56-1-58-4 
50-86 
H . 
6-36 
694 
7-2-80 
6-94 
N . 
17-11 
17-51 
11-5-14-3 
. . 
20-85 
21-75 
s . 
5-00 
2-80 
1-6-2-2 
3-30 
The main feature in the above analyses is the high percentage of 
sulphur, 5 which is in part in loose combination, and can be removed by 
alkalis or even by boiling water. 
An albuminoid obtainable from tracheal cartilage by C T. Morner, 8 
and further investigated by Hedenius, 7 is included by Hammarsten 8 
among the keratins, or as a substance intermediate between keratin and 
coagulated proteid. It contains only 1 per cent, of sulphur. Keratin 
gives the proteid reactions. 
Derivatives of keratin. — Keratin is not digestible by either gastric 
or pancreatic juice. By heating with water to 150°-200° C. it dissolves, 
forming a turbid solution. It dissolves more readily in alkalis; the 
solution contains alkaline sulphides, and substances of the proteose class, 
called keratinoses by Krukenberg. 9 
The decomposition products of keratin obtained by the use of acids 
are like those of the proteids, and include leucine, a good deal of tyrosine 
(1-5 per cent.), aspartic acid, 10 glutaminic acid, 11 ammonia, and sul- 
phuretted hydrogen, lysine, 12 lysatinine, 12 and a sulphur-containing sub- 
stance 12 which forms a compound with hydrochloric acid, with the 
formula C M H 38 N 4 12 SC1 4 . Drechsel 13 considers that some of the oxygen 
of the keratin is united to sulphur, and a part to amido-acid radicles. 
The close chemical relationship of keratin to proteid coincides with 
what is known as to its formation within the protoplasm of cells, for 
instance in the epidermis. The eleidin granules of the stratum gran ulosum 
probably represent an intermediate stage in the transformation. 
1 Ann. d. Chem., Leipzig, Bel. xlv. 
2 " Versueh. eiuer allgem. physiol. Chem.," Braunschweig, 1844-51. 
3 Kiihne and Chittenden, he. tit. 
4 See Drechsel, Ladenburg's "Handworterbnch," Bd. iii. Other analyses of horn have 
been made by Tilanus, Hoppe-Seyler's "Physiol. Chem.," S. 90 ; Lindvall, Jahresb. ii. d. 
Fortschr. d. Thier-C'hcm,., "Wiesbaden, 1881. 
5 A large number of estimations of sulphur in keratins from different sources will be 
found in a paper by Mohr, Ztschr. f. physiol. Chem., Strassburg, 1895, Bd. xx. S. 403. 
The percentage varies from 2'6 to 5 - 3. During (ibid., 1896, Bd. xxii. S. 2S1) obtained very 
similar results. 
6 Jahresb. ii. d. Fortschr. d. Thier-Chem., Wiesbaden, Bd. xviii. S. 217. 
"' Skandin. Arch. f. Physiol., Leipzig, Bd. iii. 
8 "Physiol. Chem.," 3rd German edition. S. 44. 
9 Sitzungsb. d. Jenaisch. Gesellsch.f. Med. u. Naiwrw., 1886. 
] " Krensler, Journ.f. prakt. Chem., Leipzig, Bd. cvii. 
11 Horbaczewski, Sitzungsb. d. k. Akad. d. Wissensch,., Wien, Bd. lxxx. 
12 Hedin, Jahresb. ii. d. Fortschr. d. Thier-Chem., Wiesbaden, 1893, Bd. xxii. 
13 Loc. tit. 
