INORGANIC CONSTITUENTS OF MUSCLE. 109 
is that the acid arises from the decomposition of complex molecules, 
of which proteid forms a part. It is quite possible thai the lactic acid 
may originate in both ways. 
The idea that the arid has a proteid origin was mooted by Kuhne 1 
in some of his earliest observations. He showed that uol only is the 
acid formed during rigor mortis, but also during the heat-coagulation of 
myosin. Bohm 2 supported the proteid origin of lactic acid, and his view- 
was endorsed by Hoppe-Seyler. 3 Some of my own experiments Bhowing 
the development of acid during the coagulation of pure myosin, 4 and 
Latham's theoretical views 5 on the constitution of the proteid mole- 
cule, lend in the same direction. Araki found that diminution of 
oxidation in the body, such as is produced by the inhalation of carbonic 
oxide, leads to the appearance of lactic acid (and sometimes albumin 
and sugar) in the urine. This is accompanied by increase in proteid 
katabolism; and this again, as Hainmarsten 7 points out, is in favour of 
the same view. 
Inorganic constituents of muscle. — The total ash is from 1 to To 
per cent. In it may be noted the predominance of potash among the 
bases, and of phosphoric acid among the acids. The following analyses 
are by Bunge : s — 
In parts per 1000. 
K. < i 
Xa.,0 
CaO 
MgO 
Fe 2 
P 2 5 
CI 
S0 3 
More recent work on this question is by J. Katz. 9 The flesh of a 
large number of animals w r as investigated. The following figures give the 
minimum and maximum in 1000 parts of fresh flesh — :K, 2*4 to 4-6; Xa, 0*3 
to 1-5; Fe, 0-04 to 0-25; Ca, 0-02 to 0-39; Mg, 0T8 to 0-37; P (from 
phosphates), T22 to 2-04 ; (from lecithin), 0T3 to 0-48 ; (from nuclein), 0"09 to 
0-32 ; CI, 0-32 to 0*8. 
Chemical changes accompanying the contraction of muscle — 
The physiology of muscular contraction, the influence of muscular 
work in metabolism, the gases of muscle, and other problems, will be 
studied in other portions of this work. It may not be inappr* ipriate here, 
however, to conclude this section by stating briefly the main facts, 
having a chemical bearing, relating to changes accompanying muscular 
contraction. The changes are in kind similar to those which occur in 
1 Arch.f. Anat. u. Physiol., Leipzig, 1859, S. 795 ; " Mvologisehe Untersuch.," Leipzig, 
1860, p. 184. 
2 Arch.f. d. ges. Physiol., Bonn, Bd. xxiii. S. 44. In a later paper (ibid., 1890, Bel. xlvi. 
S. 265) Bohm reaffirms his position in reference to some criticisms of Werther (ibid., S. 53). 
3 "Physiol. Chem.," S. 666, 607. 
4 Jour n. Physiol., Cambridge and London, 1887, vol. viii. p. 154. These results, how- 
ever, are criticised by v. Fiirth. 
5 Brit. Med. Journ., London, 1886, vol. i. p. 630. 
6 Loc. cit. (Xote 11, p. 106). 
7 "Physiol. Chem," 3rd German edition, S. 332. 
8 Ztschr. f. physiol. Chem., Sti assl *oilt, Bd. ix. S. 60. 
!l Arch.f. d. ges. Physiol., Bonn, 1896, Bd. lxiii. 8. 1-S.". 
I. 
II. 
4-654 
4-160 
0-770 
0-811 
0-086 
0-072 
0-412 
0-381 
0-057 
4-644 
i-58 
0-672 
0-70 
o-io 
