FOLIA DIGITALIS. 471 



tincture thus obtained was then mixed with basic acetate of lead as 

 long as it produced a {precipitate. The latter being separated, the 

 filtered liquid was concentrated and the deposit now formed, after 

 some days, removed from the aqueous liquid. It was then washed 

 with a dilute solution of carbonate of sodium, by which a yellow matter 

 {chrysophan?) was partly removed. The substance was then dried, and 

 yielded to chloroform a brownish mass, which after the chloroform had 

 been driven off, was purified by benzin. This liquid dissolved the 

 remainder of the yellow or orange matter, and a little fat, leaving crude 

 digitoxin, which is to be purified by recrystallization from warm 

 alcohol, 80 per cent,, adding a little charcoal. This purification still 

 3'ields yellowish crystals, which ought to be washed again with car- 

 bonate of sodium, ether or benzin, and then recrystallized from warm 

 absolute alcohol, containing a little chloroform. This process, however, 

 will only afibrd colourless crystals provided it be so performed as to 

 cause the separation of digitoxin on account of the cooling of the 

 solution, not by the evaporation of the solvent. If the liquid is instead 

 allowed to evaporate it will soon assume a darker coloration. In 

 the way just pointed out, yjerfectly colourless scales or needle- 

 shaped crystals of pure digitoxin are at length formed, the yield 

 being not more considerable than about one part from 10,000 of dried 

 leaves. 



Digitoxin is insoluble in water, to which it does not even impart 

 its intensely bitter ttiste as displayed in the alcoholic solution. It is 

 likewise insoluble in benzin or bisulphide of carbon, veiy spainngl}' 

 soluble in ether, more abundantly so in chlorofoi-m, the latter liquid 

 however acting but very slowly on digitoxin. Its best solvent is 

 alcohol, either cold or warm. The composition of digitoxin answers to 

 the formula, C'^H^'O". 



Digitoxin warmed with concentrated hydrochloric acid assumes a 

 yellow or greenish hue, the same which is commonly attributed to 

 commercial " digitalin." Digitoxin is not a saccharogenous matter ; in 

 alcoholic solution it is decomposed by dilute acids, and then afibrds 

 Toxiresin, an uncrystallizable, yellowish substance, which may easily 

 be separated on account of its ready solubility in ether; it appears to 

 be produced also if digitoxin is maintained for some time in the state 

 of fusion at about 240° C. Toxiresin proved to be a very powerful 

 poison, acting energetically on the heart and muscles of frogs. The 

 very specific action of foxglove is due — not exclusively — to digitoxin ; 

 it is so highly poisonous that Schmiedeberg thinks it not at all fit for 

 medicinal use, which might rather be confined to other constituents of 

 foxglove, as, for instance, to those obtained from the seeds under the 

 names of digitalin and digitalein. The latter, however, are of more 

 difficult extraction than digitoxin. 



The preparation of digitoxin is similar to that of Nativelle's crystal- 

 lized "digitalin;" the former as well as paradigitogenin^ are largely 

 found in Nativelle's digitalin. 



The Digitalin of KativeUe — The researches on digitalis of this 

 chemist, for which the Orfila prize of 6000 francs was awarded in 

 1872, have resulted in the exti'action of a crystallized preparation 



^ \ derivative of iHijUoxin as extracted by Schmiedeberg from the seeds of foxglove. 



