(7) The cause of these sudden falls is inhibition of the heart by over-activity of the vagus: cutting the vagi always terminates the effect unless delayed so long that the animal is dead: in an animal fully under atropine, these vagal actions cannot be produced. (8) If the heart is inhibited by vagal action, the respiration ceases at once, usually after one deep inspiratory sigh. (9) An inhibited heart may “escape” from vagal action before the animal is dead: frequently, however, the inhibition persists and the animal dies. (10) Struggling and breath-holding in the early stages of induction cause sudden falls of blood pressure. Many observers believe that these falls also are due to vagal activity, others hotly deny this. All are united in believing that to _press_ chloroform upon a patient who is struggling and holding the breath, is fraught with grave risk of causing sudden syncope. (11) The abnormal irritability of the vagus above referred to is a feature mainly of the induction stage, disappearing once full anæsthesia is developed. (12) It is an undoubted clinical fact that there is a risk of sudden arrest of heart’s action if the operation is begun before the stage of full anæsthesia is reached. A reasonable explanation of such accidents is furnished by supposing a reflex inhibition acting through the vagal centre already rendered hyper-sensitive by partial chloroformisation. Views of Goodman Levy. This worker has demonstrated in animals that the heart is sometimes thrown by chloroform into the condition of fibrillation--a delirium of the cardiac muscle, from which recovery is rare. It occurs in the early stage, before full anæsthesia has been reached, and is predisposed to by the infliction of trauma. The practical outcome of this is that the induction stage of chloroform should not be unduly prolonged, and that the operation should not be begun until the third stage is fully developed. So far as the author understands the views of Dr Levy, his explanation of chloroform syncope need not be taken as introducing any new principle into the administration of the drug. Even those who lay most emphasis upon the danger of using vapours of too high a percentage strength would admit the force of Levy’s contentions. As usual, safety lies in steering between two extremes. During his work on this subject, Levy further demonstrated that the introduction into the circulation of _adrenalin_ during incomplete chloroform anæsthesia was very liable to induce fatal cardiac fibrillation. He thus furnished the explanation of a number of deaths which had occurred in the practice of nose and throat specialists. Since the publication of Levy’s work, the rule has been absolute that if _adrenalin_ is to be used in a case requiring chloroform anæsthesia, the adrenalin must _precede, not follow_ the anæsthetic. Administration.