157 ARTEMISIA PAUCIFLORA 



as obtained by the process of the British Pharmacopoeia, 

 is in colourless flat rhombic prisms, inodorous, feebly bitter 

 fusible, and sublimable by a moderate heat; scarcely soluble 

 in cold water, and but sparingly so even in boiling water, 

 but abundantly in chloroform and in boiling rectified spirit. 

 It is also soluble in the fixed oils ; and solutions of the caustic 

 fixed alkalies, and forming with the latter definite compounds, 

 one of which, Santonate of Soda, has been employed in medi- 

 cine instead of santonin ; it has the recommendation over it 

 of being soluble in water. Santonin is neutral in its action on 

 test-papers, though capable of combining with bases, as just 

 described. By exposure to daylight, or to the blue or violet rays 

 of the spectrum, the crystals of santonin become yellow ; a 

 change which appears to be of a mechanical nature, for, so 

 far as is known, it is unattended by any chemical alteration. 

 Santonin is entirely destructible by a red heat with free access 

 of air. According to the investigations of Hesse, santonin is the 

 anhydride of an acid, which he has called Santoninic acid, a 

 crystalline body which, when heated to 248, is resolved into 

 santonin and water. Cannizzaro and Sestini have also shown 

 that when heated with an alkali, santonin is converted into an 

 acid which they have called santonic acid, which is isomeric with 

 santoninic acid, but not resolvable like it into santonin and water ; 

 and very recently the same investigators have noticed that santonin 

 in combining with the elements of water yields numerous bodies, 

 one of which is santonic acid. 



3. OTHEE VARIETIES OF SANTONICA. Besides the official kind 

 of santonica, as described above, and which is distinguished in 

 commerce under the name of Levant or Alexandrian Worm- 

 seed ; another variety of wormseed has also been especially 

 described by pharmacologists under the name of Barbary Worm- 

 seed. Nothing definite is known of its botanical or geographical 

 source, or of its chemical composition ; but it is said, although, 

 so far as we know, on no published authority, that santonin 

 cannot be obtained from it. Barbary Wormseed may be readily 

 distinguished from the official or Levant Wormseed by being 



