I can hardly attempt to explain clearly the _modus operandi_ of the agent. Practically, however, it answers the purpose intended. The great point is, of course, to arrest its action before it produces unconsciousness. This is effected by using it as I have described. It is requisite that the patient be carefully watched, so that the moment for administering the agent may be seized. From the experience I have now had of its use, I can estimate pretty accurately the exact time the inhalation should be resumed or discontinued. After a little practice this knowledge can be obtained by any competent observer. I have now given my anodyne mixture in 216 cases, and without in any one instance seeing a bad result _quoad_ the administration of the mixture. Of these cases many have come to me in consequence of the severity of their former labours, their extreme nervousness, and other causes. I select a few instances from my notebook in which the anodyne was employed with complete and satisfactory effects: 1. The patient was in her twenty-ninth year, by no means robust, of a nervous temperament, and looking forward to her first labour with great apprehension. 2. Was in her thirty-third year, and looked forward to her first labour with great dread. 3. Her sixth labour; all her previous labours had been very severe. 4. Her tenth labour; her previous labours very severe, and each time followed by a great deal of after-pain. 5. Her eighth labour; had suffered intensely in every previous labour, in some of which she had been delivered with instruments; had had a protracted recovery after each labour. 6. Her seventh labour; inflammation had followed each of her former labours. 7. Her fifth and sixth labours; her former labours had been very severe. 8. Her third and fourth labours; her former labours having been very severe. 9. Her first labour; very strong expulsive pains; soft parts at first being very rigid, then gradually giving way after six hours' use of the inhaler. 10. Her third labour; child's head very large and firm; much exhaustion; delivered with the short forceps, very great force requiring to be used before the head could be extracted. 11. Her first labour; very nervous and timid; with difficulty could I get her to use the Inhaler rightly, but she became much more composed towards the end, and inhaled very well. I have rarely seen stronger expulsive pains than she had towards the last; the arch of the pubes being rather contracted, and the child full-sized. 12. Her fourth labour; breech presentation; used the Inhaler for three hours.