400 PYROGALLIC ACID 



tendency to cause collapse. As an intestinal antiseptic, 

 calves and foals suffering from diarrhoea or gastric catarrh 

 receive thirty to sixty grains, dogs, grs. ii. to grs. v., while 

 horses may be given from 3J V - to 3 V J- These doses 

 may be repeated two or three times in twenty-four 

 hours. It is used as an antiseptic in surgical cases in 

 inflammation of the eyes, mammae, urino-genital organs, 

 and other sensitive parts, and as a haemostatic in capillary 

 bleeding. Kaufmann commends it in erythema, herpes, 

 and eczema, especially of the seborrhoeal type, in dogs. 

 The solutions and ointments applied contain one to ten 

 parts per hundred. 



HYDROQUINONE, chemically para-dihydroxybenzene, re- 

 sembles resorcin, but is about four times stronger, and is 

 soluble in twenty parts of water, and in alcohol and ether. 

 As it is excreted in the urine, it exerts a stimulant and 

 antiseptic action on the urino-genital mucous membrane. 



PYROCATECHIN, or ortho-dihydroxybenzene, resembles re- 

 sorcin in its actions and uses, but is about three times 

 stronger. 



PYROGALLIC ACID, or trihydroxybenzene, is obtained by 

 heating gallic acid, and is readily soluble in water and 

 alcohol. It is more irritant than most of the series, but is a 

 doubtful antiseptic. A few grains produce in dogs, as well 

 as in man, vomiting, purging, and collapse. It decomposes 

 the red corpuscles, causing shrinking of the cells and escape 

 of the haemoglobin into the plasma, where it is converted 

 into methaemoglobin. Mixed with fatty matters or starch, 

 it is sometimes used as a caustic. A 15 per cent, ointment 

 has been applied with good effects in psoriasis, but the drug 

 should not be given internally. 



SACCHARIN, glusidum, or benzoyl-sulphonimide, is deriv- 

 able from toluene of coal-tar. It is a colourless, crystalline 

 powder, two hundred and twenty times sweeter than sugar, 

 soluble in four hundred parts of water, twenty-five of alcohol, 

 forty-eight of glycerin, and slightly in ether or chloroform. 

 It is antiseptic, very stable, passes through the body un- 

 changed, and is eliminated in the urine. As it is incon- 

 vertible into sugar, it is used in tablets for sweetening 

 food, and flavouring the medicines of human patients 



