74 Com/eras [CH. 
It has unfortunately caused the death of many horses and cattle, while 
asses, mules, deer, pigs, rabbits, and pheasants have also been poisoned. 
Many cases of fatal human poisoning have also occurred. For example, 
the poisoning of a horse, and of cattle, horses, and deer were mentioned 
respectively in 1885 and 1893 (Jour. Roy. Agric. Soc.). " Through eating 
the poisonous leaves of a Yew tree, four cross-bred cattle were found 
dead in a shrubbery at Elmswell, near Driffield" (Daily Mail, 13th Dec., 
1913). Many cases of poisoning and death of animals due to eating the 
foliage direct from the trees have been recorded in the veterinary journals 
e.g. the death of 15 cattle in The Veterinary News, 7th Dec., 1912. 
Tegetmeier recorded the death of pheasants due to Yew leaves and seeds 
(The Field, llth Nov., 1893). On the other hand many cases have been 
recorded in which fatal results have not followed the ingestion of the 
leaves, and it appears that the lower branches of Yew trees in parks are 
constantly cropped by cattle without ill effects. (Trans. Chem. Soc., 
1902; Jour. Bd. Agric., 1903). 
The bark, leaves, and seeds are all poisonous, the leaves usually being 
the parts eaten. Henslow states that of 32 cases of Yew poisoning 9 
were due to the berries and the remainder to the leaves, while 20 of the 
32 cases were fatal. In 1879 R. Modlen published a circumstantial 
account of children poisoned at Oxford by the fruits, and demonstrated 
that the arillus or scarlet mucilaginous cup surrounding the ripe seed 
is not poisonous, but that the seeds are so. Apart from idiosyncrasy 
of appetite stock are perhaps more likely to eat the dark green foliage 
of the Yew in winter or during scarcity of green fodder than at other 
times. The old leaves or shoots are the most poisonous parts. 
By experiments with autumn and winter leaves Cornevin found that 
the following quantities would be necessary to kill various animals : 
Horse 0-2 Ib. per 100 Ib. live weight. 
Ass and Mule .. 0-161b. 
Cow and Sheep . . 1-0 Ib. 
Goat 1-2 Ib. 
Pig 0-3 Ib. 
Rabbit .. .. 2-0 Ib. 
Other authorities, however, quote much lower quantities a necessary 
to kill the horse and ox, and Pott says that in the case of horses 150 to 
180 grammes (0-33 to 0-4 Ib.) is sufficient to cause death in one-quarter 
to one-half an hour, without previous symptoms. Eaten by an animal 
on a full stomach a small quantity of Yew may cause little or no 
dangerous results. 
