PRODUCTS OF FERMENTATION OF CARBOHYDRATES 479 



The relation of the diamins to the condition is, however, very 

 uncertain. Cystin does not seem to exert any toxic effect, and 

 patients with cystinuria do not usually appear to suffer greatly 

 from the abnormal metabolism, the chief trouble observed being 

 due to the formation of the concretions in the bladder. Some- 

 times in children, however, emaciation and early death, with- 

 out other apparent cause, have been observed, and may be 

 due to the metabolic anomaly. 



B. PRODUCTS OF FERMENTATION OF CARBOHYDRATES 



These include practically all the members of the fatty acid 

 series, from, formic acid to valerianic acid; and the oxy-acids, 

 lactic, succinic, and oxybutyric ; also, oxalic acid, acetone, ethyl 

 alcohol, and the following gases, CO 2 , CH 4 , H 2 . For the most 

 part, the various organic acids are absorbed through the intes- 

 tinal walls, and are oxidized completely in the tissues without 

 causing any harm whatever. The possibility that acid intoxica- 

 tion may be produced in this way has been suggested, but it is 

 generally believed that this does not occur, except possibly in 

 infants. Lactic and butyric acids are formed particularly in 

 gastric fermentations in persons with deficient hydrochloric acid, 

 motor insufficiency, or organic obstruction. Most of the disturb- 

 ances observed in these conditions seem to be due to distention of 

 the stomach with gas, chiefly CO 2 , which is formed during the 

 fermentation. It is possible, however, that the organic acids 

 exercise some irritant effects on the mucous membrane ; and 

 they may also cause diarrhea, lactic and acetic acid often being 

 present in diarrheal discharges due to excessive feeding with 

 carbohydrates (Herter). 



These acids or their salts do not appear in the urine, unless 

 possibly as minute traces, except the oxalic acid. Minute 

 quantities (0.02 gm. per day) of this substance are present in 

 normal urine, but larger quantities (oxaluria) seem to depend 

 either upon the taking of food containing much oxalic acid 

 (rhubarb, spinach, etc.) or upon excessive gastric fermentation 

 of carbohydrates (Baldwin l ), and perhaps upon excessive de- 

 struction of purin bodies, from which oxalic acid may be derived. 

 Probably the small quantities of oxalic acid thus formed do not 

 cause toxic effects, and are important chiefly as causing urinary 

 concretions of calcium oxalate,. although there is evidence that 

 long-continued excretion of oxalic acid may cause renal lesions. 

 (See also consideration of oxalate calculi, pages 382, 383.) 



1 Jour. Exp. Med., 1900 (5), 27. 



