74 Coniferae, [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 

 foUage 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, 11th 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 efiects. {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 K. 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 foHage 

 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 lb. per 100 lb. live weight. 



Ass and Mule .. 0-16 lb. 



Cow and Sheep .. 1-0 lb. 



Goat 1-2 lb. 



Pig 0-3 lb. 



Rabbit .. .. 2-0 lb. 



Other authorities, however, quote much lower quantities as 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 lb.) 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 Httle or no 

 dangerous results. 



