It is not known to what extent convulsions induced experimentally by various agencies are related pathogenetically to epileptic fits. There are, however, facts which suggest that the induced convulsions have, in their several mechanisms, points in common with one another and with epilepsy. Thus, caffeine and absinthe both cause convulsions in cats; when sub-convulsant doses of both are administered together convulsion ensues, suggesting that the two drugs operate on the same mechanism (Notkin and Pike, 1931). Insulin hypoglycæmia occasionally causes convulsions; it has been shown that during hypoglycæmia in man there is a lower fit-threshold to cardiazol (Georgi and Strauss, 1938), and in cats to thujone (Keith, 1935). The elicitation of convulsions by electrical stimulation of the cortex is facilitated by camphor monobromide, absinthe (Muskens, 1928), and cardiazol (Santha, 1939) on the one hand, and in epileptics as opposed to non-epileptics, on the other (Pen-field, 1936). Hydration has been shown to play a part in the precipitation of convulsions due to hypoglycæmia (Drabkin and Ravdin, 1937), thujone (Keith, 1935), and epilepsy (Fay, 1929; MacQuarrie, 1929).