ALOE. 689 



They derive in all probability from anthracene, C^^If. 



The portion of aloes insoluble in cold water was formerly distin- 

 guished as i^gswi 0/ J. ?oes, from the soluble portion which was called 

 Bitter of aloes or Aloetin. From the labours of Kossmann (1863), these 

 portions appear to have nearly the same composition. The soluble 

 portions treated with dilute sulphuric acid, is said to yield Aloeresic 

 and Aloeretic Acids, both crystallizable, besides the indifferent sub- 

 stance Aloeretin. These observations have not to our knowledge been 

 confirmed. 



It has been shown by Tilden and Rammell ^ that the Resin of 

 Aloes may by prolonged treatment with boiling water be separated 

 into two bodies, which they distinguish as Soluble Resin A. and In- 

 soluble Resin B. With the first it is possible to form a brominated 

 compound, which though non-crystalline is apparently of definite com- 

 position. In the view of these chemists the Resin AAs n kind of anhy- 

 dride of barbaloin— Barbaloin, 2(C3*H3«0") less H^O^Aloe Resin A., 

 QC3JJ70Q27 "pijg rcsiu boilcd with nitric acid yields a large amount of 

 chrysammic acid, together with picric and oxalic acids, and carbonic 

 anhydride. Insoluble Resin B. was found to have nearly the same 

 composition as Resin A. 



Aloes treated with various reagents affords a number of remarkable 

 products. Thus, according to Rochleder and Czumpelick (1861) it 

 yields, when boiled with soda-lye, colourless crystals an inch long, 

 which appear to consist of a salt of Paracumaric Acid, together 

 with small quantities of fragrant essential oils and volatile fatty 

 acids. 



When boiled with dilute sulphuric acid, aloes yields paracumaric 

 acid, from which by fusion with caustic potash, as also directly from 

 aloes, Hlasiwetz (1865) obtained Para-oxybenzoic Acid (p. 408). 

 Weselsky (1872-73) has shown that accompanying the last two pro- 

 ducts, there is a peculiar, crystallizable acid, C"H^"0*, which he has 

 named Alorcinic Add. 



By distillation with quick-lime, E. Robiquet (1846) obtained Alo'isol, 

 a yellowish oil, which Rembold (1866) proved to be a mixture of dime- 



thylated phenol {Xylenol) C®H^ \ Xtt . with acetone and hydro- 

 carbons. 



Nitric acid forms with Barbadoes aloes, but still better, as Tilden has 

 shown, with barbaloin, Aloetic Acid, C"H^(NO")^0^, Chrysamviic Acid, 

 C'*H'(NO')'0', and finally Picric Acid, together with Oxcdic Acid. The 

 first two of these acids are distinguished by the splendid tints of their 

 salts, which might be utilized in dyeing. 



Chlorine, passed into an aqueous solution of aloes, forms a variety of , 

 substitution-products, and finally CJdoranil, C^'CTO". 



When somewhat strongly heated, aloes swells up considerably, and 

 after ignition leaves a light, slow-burning charcoal, almost free from 

 inorganic constituents. Ordinary Cape aloes, for example, dried at 

 100° C, leaves only 1 per cent, of ash. 



Commerce — There were imported into the United Kingdom in the 

 year 1870, 6264 cwt. of aloes. Of this quantity. South Africa shipped 



1 Pharm. Joum. Sept. 21, 1872. 235. 



2x 



