Yew Poiiioniiuj. 
7T> 
wliicli appears to agree with taxiiie as describe'! by Hilger 
and Brande, especially (herein differing from the descriptions of 
Marme and DragendorfI) in giving an immediate and copious 
precipitate with chloride of gold. This substance is undoubtedly 
present in hoih sorts of leaves, though very possibly there is less 
of it in one than in the other. The great difficulty of purifying 
and impossibility of crystallising taxine, and the absence of any 
published process for its estimation, or even certain identifica- 
tion, stand in the way of exact information on this point. 
The conclusions suggested to me from the imperfect, and to 
some extent conflicting, chemical evidence are : — 
Both male and female yew leaves contain an alkaloid. 
This alkaloid in both cases appears to agree with the taxine of Ililger 
and Brande. Taxine is probably tlie poison of the yew, but it is doubtful 
whether it has ever been obtained in a pure state, and its physiological 
effects have not been sufficiently studied. Other alkaloids are probably 
present in yew. 
Taxine is pre.sent in fresh yew leaves as well as in those withered or air- 
dried. It is also present in the seeds but not in the fleshy part of the fruit. 
The yew poison may be one of moderate virulence only, and may occur 
in greater percentage in male than in female trees, or the percentage may 
vary from tfee to tree without distinction of sex, and this may explain the 
capricious occurrence of poisoning. Also the half-dried leaves would be, 
cceteris paribus, more potent than the fresh. 
Further and extended chemical researches, in conjunction with physio- 
logical experiments, are necessary to clear up the matter. 
The principle having a specific uterine action is possibly not the same 
as that which causes death. 
Yew leaves merit exJiausiive chemical examination. They 
contain an unusually large proportion of substances, soluble in 
ether and alcohol, about which (excepting chlorophyll, which is 
present in large quantity) we know next to nothing. Amongst 
these, as was pointed out in The Times, is an energetic re- 
ducing agent, similar in some properties to pyrogallol. The 
male leaves used by me yielded (dry) 9‘2 per cent, to ether 
(including all the chlorophyll), and afterwards 28‘4 per cent, to 
alcohol — dotal, 37 G per cent, of their weight. The female leaves 
yielded 14'8 per cent, to ether, and then 17'9 percent, to alcohol 
— total, 32 '7 per cent. 
Itisquite true that in my Own experiments I obtained a greater 
quantity of crude alkaloid in all its different stages of impurity 
from the male leaves than from the female ; but I do not now' 
regard this result as at all conclusive. As at first precipitated, 
taxine is exceedingly' impure, and the successive stages of 
purification not only' reduce it very largely in quantity', but, I 
suspect, cause an actual alteration in composition. 
J. M. H. lilUNRO. 
