446 ALOIN ACTION ON HORSES, 



to the active principles of rhubarb and senna and other 

 members of the anthracene group of purgatives. 



Pure barbaloin is odourless ; its taste, at first slightly sweet, soon 

 becomes intensely and permanently bitter, and distinctly aloetic. It is 

 entirely combustible, burning with a yellow flame and much smoke. It 

 yields, by destructive distillation, an aromatic volatile oil, and a resinous 

 residue. It is neutral to test paper, is soluble in rectified spirit, but less 

 so in cold water, an ounce of which dissolves about a grain of aloin. The 

 solvent power both of water and alcohol is greatly increased by heat. 

 Barbaloin is also dissolved by acetic acid and alkalies, forming with the 

 latter orange-yellow solutions, which deepen in colour by oxidation. It is 

 insoluble in ether, oil of turpentine, and chloroform. Watery solutions 

 rapidly darken by exposure to air and light ; and when heated above 150 

 Fahr., the aloin is oxidised, decomposed, and converted into a resinous 

 substance of little activity. 



ACTIONS AND USES. Aloin has been used with growing 

 favour in medical practice, and with some practitioners it 

 has entirely superseded aloes. The dose for an adult is 

 from one to two grains, or about one- third of the quantity 

 of Barbados aloes usually prescribed. Drachm doses made 

 up with flour and glycerin were administered to six three- 

 parts-bred carriage horses, four and five years old, 15 to 16 

 hands high, in good health and condition, and prepared with 

 one bran mash given four hours previously. No effect was 

 observable on the pulse, temperature, appetite, or secretion 

 of urine ; the bowels were relaxed to a slight extent in two 

 of the animals, when they were exercised twenty-four hours 

 after receiving their ball ; whilst in two of the subjects 

 of experiment fulness and itching about the joints dis- 

 appeared, although no sensible effect was observed on the 

 bowels. Drachm doses of aloin, conjoined with half an 

 ounce each of gentian and ginger, proved serviceable in 

 abating febrile symptoms, and removing heat and fulness of 

 the limbs in hard- worked or grossly-fed horses. Two 

 drachms of aloin given to strong five and six years old 

 hunters, well prepared by mashes for upwards of twenty-four 

 hours, caused, in thirteen or fourteen hours, abundant fluid 

 evacuations. Nothing notable was observed as to the 

 pulse or temperature ; there was less dulness or loss of 

 appetite than usually accompanies the full action of the 

 ordinary aloetic ball ; there was no nausea or griping ; 

 the purging usually continued six or eight hours. In these 





