3. The respiratory centre is at first perceptibly stimulated, and respiration is therefore deeper and quicker than normal. The stimulant effect rapidly passes away and gives place to a stage of depression. In the majority of cases, death appears to take place from paralysis of the respiratory centre, the heart still showing a little power of contraction after respiration has ceased. There is therefore a fair prospect of recovery if artificial respiration be resorted to promptly. Methods of Administration. OPEN METHOD. The extreme volatility of the drug has discouraged most anæsthetists from giving it upon an open mask. Hornabrook, of Melbourne, advocates this system, however. His mask fits the face accurately, and his whole method is strictly perhalational. He uses some 4–6 c.c. of the drug for a child, 6–8 c.c. for an adult, and achieves his anæsthesia in a minute to a minute and a half. He also advocates open ethyl chloride as a preliminary to open ether. For some twelve months, the author adopted the method. At the end of that time he came to the conclusion that while it greatly facilitated the induction stage of open ether, it appeared to increase the after sickness. He therefore abandoned it, though rather reluctantly. CLOSED METHOD. This is the usual means employed. A variety of inhalers have been produced on the market, one of which is shown in Fig. 41. Essentially all consist of:-- (_a_) A face-piece which must fit the face with reasonable accuracy. (_b_) A one-gallon rubber bag attached to the mask by a T-piece. (_c_) A glass vial, with numerals from 1 to 5 marked on the outside to facilitate the measurement of the drug in c.c. Into this the drug is squirted from the makers’ tube. The vial is attached to the T-piece (or alternatively the bottom of the bag) by a rubber tube. [Illustration: FIG. 41.--Ethyl Chloride Inhaler.] Administration.