62 CHEMICAL CONSTITUENTS OF BODY AXD FOOD. 
snails. 1 A mucinogen is found in the investment around frogs' eggs; 2 
it is also the must important constituent of the intercellular or ground 
substance of connective tissues, and has been especially investigated 
in the jelly-like connective tissues (vitreous humour, 3 Whartonian 
jelly 4 ), and in tendon. 5 
Elementary analysis of different mucins has given different results, as will 
be seen from the following table : — 
Snail Mucin. 
Ten lion 
Mucin. 
SUBM VX1I.L AKY MOI IN. 
Haminarsten.G 
Loebisch.7 
Chittenden .8 
Hainmarsten.9 ( >bolensky.M 
c . 
50-32 
48-3 
18-26 
18-84 
52-31 
H . 
6-84 
6 \ 1 
6-49 
G-80 
7-22 
N . 
13-65 
1175 
11-51 
12-32 
11-84 
S . 
1-75 
0-81 
2-31 
0-84 
. 
27-44 
32-70 
31-43 
31-20 
The mucins thus contain less carbon, and considerably less nitrogen, 
than proteids. 
Deco77iposition piwducts of mucin. — By the action of superheated 
steam, a carbohydrate is split off from mucin, which was called animal 
gum by Landwehr. 11 He assigns to it the formula (C 6 H ]0 O 5 ). By 
the action of dilute mineral acids this is converted into a reducing but 
non-fermentable sugar or gummose (C 6 H 12 6 ). The gum-like substance 
obtained from submaxillary mucin contains nitrogen. 1 - The sugar 
obtained from tendon mucin by Chittenden yielded an osazone melting 
at 160°, and resembled that obtained from pentoses. F. Midler 13 has 
investigated the mucin of sputum. He found it yielded as much as 
25 to 32 per cent, of a reducing substance : this is not a pentose, but is 
probably glucosamine. 
i Eichwald, Ann. d. Cfiem., Leipzig, 13d. cx.x.xiv. 
2 Giacosa, Ztschr. f. physiol. Chem., Strassburg, Bd. vii. S. 40: Hammarsten. Arch. f. 
<1 . ges. PhysioL, Bonn, Bd. xxxvi. ; Wolfenden, Journ. Physiol., Cambridge and London, 
vol. v. p. 91. 
3 R. A. Young, Journ. PhysioL, Cambridge and London, 1894. vol. xvi. p. 325 : C. Th. 
Mbrner, Ztschr. f. physiol. Chem., Strassburg, 1893, Bd. xviii. S. 24"). References to previous 
literature will be found in these papers. Young arrived at the conclusion that the principal 
substance in vitreous humour is mucinogen, not mucin. 
4 Jernstrora, Jahresb. ii. d. Fortschr. d. Thier-Chem., Wiesbaden, 1S89, Bd. x. S. 34. 
Young, loc. tit., separated two mucins from the "Whartonian jelly, one soluble, the other 
insoluble in excess of acetic acid. 
5 Rollett, Sitzungsb. d. k. Akad. d. Wissensch., Wien, Bd. xxxix. S. 308. Strieker's 
<; Handbuch," Bd. i. S. 72. Loebiscb, Ztschr. f. physiol. Chem., Strassburg, Bd. x. S. 40 ; 
Chittenden and (lies. Journ. Exper. Med., Baltimore, 1896, vol. i. p. 1SS. 
,; Arch./, d. ges. Physiol., Bonn, Bd. xxxvi. "' Loc. tit. 
8 Loc. cit. The high percentage of sulphur found is attributed by Chittenden to proteid 
impurities. 
9 Ztschr. f. physiol. <'lirm., Strassburg, Bd. xii. 
10 Arch. f. d. ges. Physiol., Bonn, Bd. iv. S. 336. Probably Obolensky's preparation 
was not so pure as Hammarsten's. 
11 Ztschr. f. physiol. Chem., Strassburg, 1881, Bd. viii. S. 124, 199; Arch. f. d. <jes. 
Physiol., Bonn, Bde. xxxix. and xl. 
12 Hammarsten, " Physiol. Chem.," 3rd German edition, p. 39. 
13 Centralbl.f. Physiol., Leipzig, 1896, Bd. x. S. 480; Sitzungsb. d. Gcsellsch. z. Befbrd. 
d. ges. Naturw. zu Marburg, 1896, No. 6. 
