_Toxic Principle._ The grains only are harmful, and contain the narcotic alkaloid _Temuline_ (C_{7}H_{12}N_{2}O), which Hofmeister showed to be a strong nerve poison, and which is said to occur to the extent of 0·08 per cent. in the seeds. Other authorities impute the toxic property to _Loliine_, while Smith states that the toxic principle is _Picrotoxin_. In relation to the grain fungal hyphæ have usually been found, though not invariably, 20 to 30 per cent. of the plants sometimes being free from it. The fungus (_Endoconidium temulentum_) is propagated vegetatively by means of mycelium. It appears to live symbiotically in the maturing grain, and perhaps to a slight extent renders possible the assimilation of nitrogen from the atmosphere; but Freeman observed that though generally stimulating to the Darnel, it is occasionally injurious to it. Esser sums it up by saying that according to most authorities who have investigated Darnel the fungus alone contains the toxic substance—the Temuline—and hence the grains in which the fungus does not occur should be harmless. The fungus is found in Darnel grain in all countries—Chile, Brazil, S. Africa, Persia, Spain, France, Sweden, Germany, etc. So far as can be ascertained there have been no feeding experiments to determine the difference in toxic character between fungus-infested and fungus-free grains. The dangerous properties are said to be most pronounced in wet seasons. _Symptoms._ In France Darnel is called _Ivraie_, because, when brewed with barley, it acts as a narcotic intoxicant. Darnel poisoning induces giddiness, drowsiness, uncertain gait, and stupefaction (Müller), and, in the older animals, vomiting, convulsions, loss of sensation and death (Pott). The symptoms in the _horse_ are dilatation of pupils, vertigo, uncertain gait, and trembling. The animal falls, the body is cold and the extremities are stiff, respiration is laboured, the pulse is slow and small, and there are convulsive movements of the head and limbs. There is rapid enfeeblement, and death may occur within thirty hours. In _pigs_, foaming, convulsions and paralysis have been observed; the stomach and intestines were inflamed and the lungs congested. REFERENCES. 4, 16, 73, 81, 106, 128, 130, 141, 190, 203, 204, 205, 213, 233, 235, 254. EQUISETACEÆ.