_Fatal Dose._--One drachm, but recovery has taken place after much larger quantities, if well diluted or taken after a meal.
_Tests_ are not necessary, as the smell of carbolic acid is characteristic.
_Local action_ of carbolic acid produces anæsthesia and necrosis. Accidents sometimes happen from too strong lotions applied as surgical dressings.
=Lysol= is a compound of cresol and linseed-oil soap, and is much less toxic than carbolic acid.
=Caustic Potash= occurs in cylindrical sticks, is soapy to the touch, has an acrid taste, is deliquescent, fusible by heat, soluble in water. =Liquor Potassæ= is a strong solution of caustic potash, and has a similar reaction. =Carbonate of Potassium=, also known as potash, pearlash, salt of tartar, is a white crystalline powder, alkaline and caustic in taste, and very deliquescent. The bicarbonate is in colourless prisms, which have a saline, feebly alkaline taste, and are not deliquescent.
_Symptoms._--Acrid soapy taste in mouth, burning in throat and gullet, acute pain at pit of stomach, vomiting of bloody or brown mucus, colicky pains, bloody stools, surface cold, pulse weak. These preparations are not volatile, so that there is not much fear of lung trouble. In chronic cases death occurs from stricture of the oesophagus causing starvation.
_Post-Mortem Appearances._--Soapy feeling, softening, inflammation, and corrosion of mucous membrane of mouth, pharynx, oesophagus, stomach, and intestines. Inflammation may have extended to larynx.
_Method of Extraction from the Stomach._--If the contents of the stomach have a strong alkaline action, dilute with water, filter, and apply tests.
_Tests._--The carbonates effervesce with an acid. The salts give a yellow precipitate with platinum chloride, and a white precipitate with tartaric acid. They are not dissipated by heat, and give a violet colour to the deoxidizing flame of the blowpipe. Stains on dark clothing are red or brown.
_Treatment._--Vinegar and water, lemon-juice and water, acidulated stimulant drinks, oil, linseed-tea, opium to relieve pain, stimulants in collapse. Do not use the stomach-tube. The glottis may be inflamed, and if there is danger of asphyxia, tracheotomy may have to be performed.