v] Coniferge 75 



Toxic Principle. The researches of Marme pointed to the alkaloid 

 Taxine (Cj^HggNOio) as tte toxic substance. Later investigations of 

 Thorpe and Stubbs confirmed this view, and it is generally agreed that 

 this substance is the toxic principle, though doubts as to its being the 

 only poison have been expressed. Taxine has a bitter taste, is a heart 

 depressant, and may cause death from suffocation. The yew also 

 contains a considerable quantity of Formic Add, and the acrid, 

 irritant volatile Oil of Yew. 



Thorpe and Stubbs {Trans. Chem. Soc, 1902) found in the fresh 

 leaves of the common Yew from 0-1 to 0-18 per cent, of Taxine. In an 

 investigation of the Irish Yew (T. baccata var. fastigiata) Moss found 

 Taxine present as follows : — 



Leaves from female tree, fresh . . . . 0-596 per cent. 



9> >3 99 93 J9 . . . . 0'623 „ 



Seeds from fruit of same tree 0-079 „ 



Another female tree — leaves 0-323 „ 



.. » „ seeds 0-082 „ 



In the leaves of the male common Yew Moss found 0-082 per cent, 

 of Taxine, or less than one-half the quantity found by Thorpe and 

 Stubbs. 



Symptoms. The Yew is irritant and narcotic, and the poison is 

 not cumulative, but on the other hand rapidly effective, so that animals 

 may die apparently suddenly, no previous symptoms having been 

 observed. 



When small quantities only have been taken the closest attention 

 is necessary to discern the symptoms, which simply consist in a httle 

 excitement with a slight rise in temperature. 



With larger (but not fatal) quantities the first symptom, excitement, 

 is more pronounced and is followed by nausea, and (where possible) 

 vomiting. There is a pronounced slackening of respiration and circula- 

 tion, the pulse being small, slow, and difficult to perceive, and the 

 movement of the flanks very slow; sensibihty is diminished. There 

 is a fall in temperature, the skin and extremities being cold. The head 

 is lowered, the eyes are closed and there is decubitus. In some cases 

 pregnant animals have aborted. In the horse there are muscular tremors 

 and frequent urination. In cattle and sheep rumination is suspended 

 and there is more or less pronounced tympanites, with eructation, 

 nausea, and sometimes vomiting. Pigs bury the head in the htter and 

 sleep, their sleep being interrupted from time to time by nausea and 

 groaning; or the animals rise, stagger about, and lie down again. 



