CAEBOLIO ACID 327 



horse, and is thought to be a product of intestinal ferment- 

 ation. In large toxic doses most of the carbolic acid is 

 eliminated in the urine unchanged. Part, however, is 

 oxidized into two bodies — pyrocatechin an,d hydroquinone — 

 and these, as well as phenol, unite with sulphuric and 

 glycuronic acids in the tissues. Thus phenol is eliminated 

 in the urine as double sulphates and glycuronates of phenol, 

 pyi-ocatechin and hydroquinone. The last two are unstable 

 and further undergo oxidation into dark substances, color- 

 ing the urine, which grows darker on exposure to the air. 

 The normal sulphates are absent in the urine following 

 carbolic acid poisoning. 



Toxicology. — Carbolic acid ranks as one of the most 

 powerful poisons — together with prussic acid and nitio- 

 benzole — in existence. Several cases of death in man have 

 occurred after the ingestion of one-half an ounce of carbolic 

 acid ; and the smallest fatal human dose on record appears 

 to be about one drachm. One or two drachms are fatal to 

 dogs, and a dose as small as 15 grains is said to have caused 

 I the death of a dog, while the lethal amount for the horse is 

 about one ounce. Many cases of accidental poisoning have 

 occurred from absorption of carbolic acid when applied 

 externally for surgical purposes in dressings or solutions 

 upon raw surfaces. The symptoms are the same as when 

 absorption occurs from the digestive tract. Extensive 

 local sloughing, after continuous treatment with moist 

 carbolic applications, is occasionally seen. Dogs and cats 

 are particularly susceptible to the action of phenol. The 

 milder symptoms of poisoning include dulness, loss of 

 appetite, m,uscular weakness and trembling, and dark-colored 

 urine having the odor of carbolic acid. After lethal doses 

 death may be instantaneous through respiratory arrest, the 

 heart continuing to beat for a time. The more ordinary 

 symptoms in severe poisoning in all animals are : trembling, 

 rarely vomiting and purging, restlessness, salivation, loss of 

 muscular power (animal reels and falls), diminution of 

 sensibility, anaesthesia, dyspnoea; the breathing is rapid, 



Digitized by Microsoft® 



