SALIX FRAGILIS. 
171 
and May, and is found growing in woods and moist places ; and the 
Salix Caprea, (round leaved) is also indigenous and floweri^ hi 
April. 
Sensible and Chemical Qualities and Properties. 
The dried bark is inodorous, bitier and austere. "The bark of the 
white willow only has been chemically examined ; but as the other 
two species agree with it in their sensiltle qualities, it is probable 
that they agree also in other lesfiects. Water extracts its virtues 
and affords a decoction of a reddish colour, which is precipitated by 
a solution of isinglass, the carbonates of potass and of ammonia, 
and by lime water, which throws down a precipitate, at first blue, 
and afterwards buff-coloured; sulphate of iron also produces a 
dark green precipitate. The watery extract is reddish, brittle, has 
a bitter taste, and does not dejiquesce. Digested in alcohol this bark 
affords a greenish yellow tincture, which water renders turbid. 
When evaporated the extract is of a bright yellow colour, bitter, 
melts at a moderate heat, and emits an aromatic odour. The con- 
stituents therefore of white willow bark, and probably of the two 
other species also, are tannin, bitter resin, extractive, and gluten." 
Medical Properties, &c. The bark of the branches of this, 
and most of the other willows, is powerfully astringent ; and hence 
most of them have been considered as good substitutes for Peruvian 
bark : upon trial they have been found to stop the paroxysms of in- 
termittent fever,* but in points of efficacy they are not to be com- 
pared to Peruvian bark, neither do they, like the latter, contain any 
cinchonin. We should be inclined to consider the willow barks as 
mere tonic and astringent medicines. As such they have been ad- 
ministered with success in some cases of debility, dyspepsia, and 
pulmonary haemorrhage; and we are told by Dr. A. T. Thomson, 
that in phthisis and hectic fever, they have apparently been more 
serviceable than the cinchona. The dose of the powdered bark is 
from thirty to sixty grains, or it may be given in the form of decoe- 
tioD, either alone or combined with aroraatics. c 
Off. The Bark. 
* Vide Med. Comment, vol. v. p. 298. Phil. Trans, vol. liii. p. 195. Gerliard Mat. 
Med. p. 301. With Bergius it did not succeed, lie sajs, " Ego hunc corticem in febri- 
bus iBtermitteotibus iterum iternmque exbibui, sed irrito conatu." 
