ioS THE CHEMISTRY OF THE TISSUES AND ORGANS. 
stated by Berzelius, 1 Du Bois-Beymond, 2 Kiihne, 3 and Heidenhain. 4 It 
may be readily detected in an ethereal extract by Uffelmarm's reaction. 5 
Lactic acid is formed, not only after death, but also on activity 
during life : it is doubtless one of the acid products the accumulation 
of which produces fatigue? though the possibilities of basic products 
being also produced and causing fatigue by their influence on the 
central nervous system should not be overlooked. 7 
A number of recent researches have, however, thrown doubt on the ques- 
tion whether any free lactic acid is actually formed under these circumstances. 
In determining this question, it is very important to know the indicator 
employed in the investigation; hut even with the same indicator the results 
obtained by different workers are sometimes discordant. One of the best 
indicators for detecting weak acids is phenolphtalein. 
Moleschott and Battistini 8 found a rise of acidity during rigor, while 
Blome 9 did not. Warren 10 finds in fatigue that the acidity is increased, 
but that the number of acid molecules is diminished. This is explained by 
supposing that in resting muscle the anhydride, and in contracting muscle 
the free acid, is present, which latter combines with twice as much base as 
the anhydride. 
Gleiss n agrees with the generally accepted view, that the acidity of contract- 
ing muscle is due to lactic acid, and finds that the slowly contracting red 
muscles of the rabbit, or the very slowly contracting muscles of the tortoise, 
become acid less rapidly than ordinary voluntary muscles. 
Weyl and Seitler 12 were the first to point out that the increase of acidity 
may he at least in part due to acid potassium phosphate, produced from the 
alkaline phosphate by the development of new phosphoric acid from organic 
compounds, like lecithin and nuclein. Irisawa 13 takes a similar view in 
reference to the acidity of dead organs like the liver and pancreas. The 
most careful work in this direction, however, is that of Rohmann. 14 He used 
lacmoid and turmeric as indicators, and found that fresh muscle is alkaline to 
lacmoid, and neutral or weakly acid to turmeric. During tetanus and rigor, 
the alkalinity to lacmoid decreases, and the acidity to turmeric increases. He 
attributes the acid reaction to monopotassium phosphate (KH.,P0 4 ), and 
the alkaline reaction to dipotassium phosphate (K 2 HP0 4 ), and to sodium 
bicarbonate. If lactic acid is formed, none is free. He admits that ether 
will extract lactic acid from muscle, but it will do so from alkaline muscle, 
and is produced by monopotassium phosphate turning it out of combination 
during the process of extraction. 
With regard to the origin of lactic acid, 0. Xasse believes it comes 
from the glycogen. This is the simplest view of the matter to take, 
and it is supported by some work of Ekunina. 15 Many facts, however, 
do not fit in with this explanation ; and the view very generally held 
1 "Lehrbuch d. Chem.," vol. vi. p. 557. 
2 " Gesammelte Abhandl. zur allgemein. Musket unit Nerven Physik," Leipzig, 1877. 
3 <: Untersucli. u. das Protoplasma," Leipzig, 1864. 
4 "Mechanisehe Leistung," Leipzig, 1861, S. 143. 
5 A dilute solution of ferric chloride and carbolic acid, which is violet, is turned yellow 
by a trace (1 in 10,000) of lactic acid {Ztschr.f. klin. Med., Berlin, Bd. viii. S. 392). 
^ Ranke, "Tetanus." Leipzig, 1865, p. 350. 
7 A. Mosso, Trans. Intermit. Med. Cong., Berlin, 1S90. 
6 Arch. Hal. dc. biol., Turin, vol. viii. p. 90. 
9 Arch. f. exper. Path. u. PharmakoL, Leipzig, 1890, Bd. xxviii. S. 113. Blome's 
results have been much criticised bv Rohmann ; Arch. f. d. ges. Physiol., Bonn, 1892, lid. 
1. S. 84, ibid., 1893, Bd. lv. S. 589. 
10 Arch. f. d. ges. Physiol, Bonn, Bd. xxiv. S. 391. u Ibid., Bd. xli. S. 69. 
12 Ztschr. f. 2)h>/siol. Chem., Strassburg, Bd. vi. S. 557. 13 Ibid., Bd. xvii. S. 340. 
14 Loc. cit. 15 Jouni. f. prakt. Chem., Leipzig, X.F., Bd. xx. 
