There are a number of plants which, while not necessarily physiological poisons, may induce injuries of a severe character when taken by animals, and by causing festering may bring about septic poisoning. For example the sharp pointed fruits of _Stipa pinnata_ and _Nardus stricta_ may cause injury to the skin and mouth, piercing the palate and causing inflammation, and when eaten may even perforate the wall of the intestine and cause death; and the awned glumes of species of _Bromus_ or the spikelets of Hordeum may injure the gums, causing inflammation, ulceration, sores, the formation of pus, and loss of teeth. The _Bromus_ and _Hordeum_, also, together with over-matured “heads” of _Trifolium incarnatum_, may give rise to Phytobezoars or balls in the stomach of horses and cattle (60, 119). The sharp pointed fruits of _Erodium cicutarium_ may cause local irritation by working into the wool of sheep. _Aira caespitosa_ may also cause injury to the mouth of stock. A case is recorded in New South Wales in which cattle and horses ate Shepherd’s Purse (_Capsella Bursa-pastoris_). The cattle were unaffected, but the horses scoured, though most of them soon recovered when removed from the cultivated paddock containing the weed. Two young horses, however, showed signs of colic, became bloated, and died. It was then found that they contained balls of fibrous material (one weighed 1 lb. 9½ oz.) which consisted to the extent of nearly 50 per cent. of fibres from Shepherd’s Purse, and death was due to simple mechanical obstruction of the bowel (155). Chickweed (_Stellaria media_) has been found to cause digestive disorder in lambs and sheep when eaten in large quantities (48), and has caused the death of many a lamb. It would appear to be due entirely to the formation of large lumps of the weed in the stomach, and subsequent fermentation (_Farmer and Stockbreeder_, Mar. 16, 1908). According to Cornevin, Black Bindweed (_P. Convolvulus_ L.) may prove injurious, owing to the occurrence of the hard, trigonous, and pointed “seeds” in cereal grains. Galtier published facts which show that oats which contain too many of the “seeds” may, by prolonged use, occasion a more or less serious enteritis, which is sometimes fatal, particularly when the grain is fed to greedy horses which scarcely grind their food (73). The fruits or “seeds” of Knot-weed (_Polygonum Aviculare_ L.) may similarly prove injurious, and probably the seeds of other plants. CHAPTER IX CLASSIFICATION OF POISONS.