554 MUSCLES. 



The fermentation lactic acid, which is formed from lactose by allow- 

 ing milk to sour, and by the acid fermentation of other carbohydrates, 

 is considered to exist in small quantities in the muscles (HEINTZ), in the 

 gray matter of the brain (GSCHEIDLEN), and in diabetic urine. The 

 occurrence of fermentation lactic acid in the brain and other organs 

 has recently been disputed by MomYA. 1 During digestion this acid is 

 also found in the contents of the stomach and intestine, and as alkali 

 lactate in the chyle. The paralactic acid is, at all events, the true 

 acid of meat extracts, and this alone has been found with certainty in 

 dead muscle. The lactic acid which is found in t^ie brain, spleen, lym- 

 phatic glands, thymus, thyroid gland, blood, bile, pathological transudates, 

 osteomalacious bones, in perspiration in puerperal fever, in the urine 

 after fatiguing marches, in acute yellow atrophy of the liver, in poison- 

 ing by phosphorus, and especially after extirpation of the liver seems 

 to be paralactic acid.. 



The origin of paralactic acid in the animal organism has been sought 

 by several investigators, who took for basis the researches of GAGLIO, 

 MINKOWSKI, and ARAKI, in a decomposition of protein in the tissues. 

 GAGLIO claims a lactic-acid formation by passing blood through the sur- 

 viving kidneys and lungs. He also found 0.3-0.5 p. m. lactic acid in the 

 blood of a dog after protein food, and only 0.17-0.21 p. m. after fasting 

 for forty-eight hours. According to MINKOWSKI the quantity of lactic 

 acid eliminated by the urine in animals with extirpated livers is increased 

 with protein food, while the administration of carbohydrates has no 

 effect. ARAKI has also shown that if we produce a scarcity of oxygen 

 in animals (dogs, rabbits, and hens) by poisoning with carbon monoxide, 

 by the inhalation of air deficient in oxygen, or by any other means, a 

 considerable elimination of lactic acid (besides dextrose and also often 

 albumin) takes place through the urine, an observation which has been 

 confirmed by SAITO and KATSUYAMA. 2 As a scarcity of oxygen, accord- 

 ing to the ordinary statements, produces an increase of the protein 

 catabolism in the body, the increased elimination of lactic acid in these 

 cases must be due in part to an increased protein destruction and in part 

 to a diminished oxidation. 



ARAKI has not drawn such a conclusion from his experiments, but 

 he considers the abundant formation of lactic acid to be due to a cleavage 

 of the sugar formed from the glycogen. He found that in all cases where 

 lactic acid and sugar appeared in the urine the quantity of glycogen in 



1 Heintz, Annal. d. Chem. u. Pharm., 157, and Gscheidlen, Pfliiger's Arch., 8, 

 171; Moriya, Zeitschrift f. physiol. Chem., 43. 



2 Gaglio, Arch. f. (Anat. u.) Physiol., 1886; Minkowski, Arch. exp. Path. u. Pharm., 

 21 and 31; Araki, Zeitschr. f. physiol. Chem., 15, 16, 17, and 19; Saito and Katsuyama, 

 ibid., 32. 



