546 AN AMERICAN TEXT- HOOK OF PHYSIOLOGY. 



standing with PeniciUium glaucurn the left lactic acid is destroyed more freely 

 than is the right, and the solution rotates polarized light to the right. 1 



The right ethidene lactic acid, called also sarco- or para-lactic acid, is that 

 which is found in muscle, blood, in various blood-glands, in the pericardial 

 fluid, and in the aqueous humor. Likewise it is found in the urine after 

 strenuous physical effort, after CO-poisoning, in yellow atrophy of the liver, 

 in phosphorus-poisoning, in trichinosis, and in birds (geese and ducks) after 

 the liver has been extirpated, and it is found in increased quantities in the 

 blood and in all the organs of animals poisoned with arsenic.- It is some- 

 times present in diabetic urine. Para-lactic acid is a normal constituent of the 

 blood and increases in amount after work or tetanus. It accumulates in the 

 dying muscle {rigor mortis), causing the formation of KH 2 P0 4 , which gives 

 the acid reaction and causes coagulation. 3 Some believe that free lactic acid 

 itself is present and aids in the coagulation. Regarding its origin, it has been 

 shown that it increases in amount in the dying muscle without simultaneous 

 decrease in the amount of glycogen. 4 It has also been shown that the large 

 increase of lactic acid in the extirpated liver is only due to the production of 

 fermentation lactic acid from glycogen.' On extirpation of the liver in geese, 6 

 ammonia and para-lactic acid replace the customary uric acid in the excreta, 

 and previous ingestion of carbohydrates or of urea will not increase the 

 amount of para-lactic acid. The lactic acid excreted is proportional in 

 amount to the proteid destroyed and to the ammonia present. It may fairly 

 be concluded that it always owes its origin to proteid. 



Hoppe-Seyler ' says that lactic acid appears in the urine only when there is insufficient 

 oxidation in the body, and attributes its derivation to the decomposition of glycogen. In 

 ( '( ^-poisoning Araki" finds as much as 2 per cent, of lactic acid (reckoned as zinc lactate in 

 a rabbit's urine. Minkowski, 9 on the other hand, denies the insufficient-oxidation theory, 

 and maintains that the destruction of lactic acid depends on a specific property of the 

 liver, the normal action being either destruction in the liver itself or in other organs 

 through the medium t>\' a substance (enzyme?) produced in the liver. 



One may interpret Araki's experiment as showing that considerable quantities of lactic 

 acid arc constantly produced in metabolism, but are normally swept away and burned; the 

 CO-poisoning would prevent the normal combustion. The accumulation in muscle after 

 stoppage el' the blood current [rigor mortis) would then be only a continuation of the nor- 

 mal process of decomposition. 



Cyste'in, a-Amido-a-thiopropionic Acid. — This substance has the formula 



1 Berichte der deulschen chemischen Gesellschaft, Bd. L6, S. 2720. 

 -' Morisbima : Archiv fiir exper. Pathologic umd Pharma/eologie, 1899, Bd. 43, S. 217. 

 3 Astaschewski : Zeitsehrifl fur physiologische Chemie, 1880, Bd. 4, S. 403; [risawa, Ibid., 1893, 

 Bd. 17, S. 351. 



'Boehm: P Irchiv, 1880, Bd. 23, S. 44. 5 Morisbima : Loe. cit. 



,; Minkowski: Archiv fur exper. Pathologic mul Pharmacologic, 1S86, Bd. 21, S. 41. 



7 /■ ttschrift zu /■'. Virchovfs 70. Geburtstag. 



- Zeitsehrifl fur physiologische Chemie, 1894, Bd. 19, S. 426. 



s hoc. cit., and Archiv fiir exper. Pathologic und Pharmakologie, 1893, Bd. 31, S. 214. 



