CARBOLIC ACID 309 



death occurs after lethal amounts from paralysis of the 

 respiratory centre. 



Nervous System. — T'he brain is depressed by toxic doses 

 of carbolic acid, and stapor and coma occur. The convul- 

 sions appearing in carbolic acid poisoning are due to pri- 

 mary stimulation of the spinal motor area, which is finally 

 depressed and paralyzed. When locally applied, carbolic 

 acid depresses and paralyzes the peripheral sensory nerves. 



Temperature. — Carbolic acid, in medicinal doses, slightly 

 lowers temperature both in health and fever, but is not suffi- 

 ciently antipyretic to be suitable for such a purpose in prac- 

 tice. It depresses heat production and increases heat loss. 



Elimination. — Carbolic acid is eliminated by all ordinary 

 channels, but mainly by the kidneys. The urine becomes 

 dark colored — a very characteristic sign — even after large 

 medicinal doses. The sole cause of this urinary coloration 

 has not yet been fully determined. Phenol normally occurs 

 in small quantities in the urine of man and animals. Three 

 grains have been recovered from the urine passed in 24 

 hours by a horse, and is thought to be a product of intes- 

 tinal fermentation. In large toxic doses some carbolic acid 

 is eliminated in the urine unchanged. In smaller quantities, 

 part of the acid is decomposed, and part eliminated as sul- 

 phocarbolates of potassium and sodium, and a substance 

 called glycuronic acid, while a portion is oxidized in the 

 system into two bodies, hydroquinone and pyrocatechin. 

 The latter accounts, in part, for the dark coloration of the 

 urine, for pyrocatechin can only exist in an alkaline urine. 

 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 nitro- 

 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 



