Toxicological Study of Toads

All the reports of which there are few published on the skin-toxity of toads, treated the secretion of the so-called poisonous parotid gland. Therefore the writer having severed the headskin, particularly the so-called poisonous parotid glands, and using the body skin alone in making extract with a saline solution of 0.6 %, examined its toxic effect and obtained the following results. 1. When he intravenously injected into rabbits 1.5-1.0 c.c. per 1 kg. body weight, the animals lay oil their sides, in depressed condition, followed by the dilatation of the pupil, convulsions and agony, after which they died. Post-mortem examinations revealed that the heart had stopped in systole and the visceral blood vessels had somewhat contracted. 2. When 0.5-0.8 c.c. of the extract was injected into the lymph sacs of frogs, they stopped all jumping within 10 minutes, and turned on their backs did not regain their ordinary position. The respirations decreased and finally the whole system relaxed and they died. Anatomical examination showed that the heart had stopped in systole. 3. The blood pressure determining at the carotid artery in cats and rabbits rose 50-70 % high after an intravenous injection with 0.5-1.0 c.c. of the extract had been given. But when 1.5-2.0 c.c. was injected, the blood pressure went up once then rapidly fell below normal and in some cases it caused death. Post-mortem, examinations showed that the heart, and blood vessels of internal organs were in the same conditions described in the other cases. The change in the blood pressure of the pulmonary artery was parallel with that of the grand circulation. 4. As to its action on the isolated hearts, pulsations become stronger but fewer in number at first, then grew irregular, and stopped in systole. 5. When the frog legs are perfused with this extract using the method of Trendelenburg, the vessels contracted remarkably. From the action on the heart and blood vessels, the rise and fall of the blood pressure seems to be due to the changes of these organs. Furthermore, such changes of the heart and blood vessels occur without any relation to either the central or peripheral vasomotor nerves. 6. The smooth muscle-organs such as the wombs of guinea-pigs and white rats as well as that and the isolated intestines of rabbits were contracted. The nervous system had nothing to do with them. 7. Surface anesthesic effect of this extract was proved determining the reflex-time of a decaptitated frog, moreover it paralyze the skeletal muscles of aa frog exerting directly on it. 8. The poisonous substance which has such toxic effects can also be extracted with alcohol. It is an acid substance yellowish brown in colour. It is easily soluble in alkaline water, ether, benzol and chloroform. It cannot be influenced by boiling and drying, and it also stands acid, alkali and formaldehyd. It can be absorbed by absorbing substances. 9. When the colour reaction of this substance was examined, it gave positive Liebermann-Bouchard and Salkowski reactions. Moreover when the substance plus a small amount of each of ice-acetic acid and acetylchlorid and a tiny grain of incalescent chlortinc was heated, it first turned green then brown. [Cf. Original (Japanese) p. 331.]