Chloroform being more pleasant and more efficient quickly replaced ether. While the fact that it is more dangerous than ether was soon discovered, from the greater number of fatalities in surgical cases, the delusion was long main tained that the pregnant woman had a special tolerance for chloroform. Within recent years most authorities have shown apreference for ether because of its greater safety, and, with the newer methods of administration, its effi ciency has been increased to some degree. Both have proved of great value in many thousands of cases. Some deaths undoubtedly have re sulted from their use but they have been the means of saving hundreds of lives.
Both ether and chloroform have the fault of opium in that they weaken the uterine con tractions and anaesthetize the fetus in utero. Because of their limitations and slightly greater dangers these anaesthetics are gradually being supplanted by nitrous oxid-oxygen analgesia.
Klikowitsch of Petrograd applied nitrous oxid-oxygen analgesia to 25 obstetrical cases in 1880. He found that three or four inhalations of this mixture rendered the uterine contrac tions painless without clouding the conscious ness. He observed that its action was different from that of opiates, ether and chloroform, in that the uterine contractions were often stimu lated and that in no case was there any diminu tion in their frequency or strength. The fol lowing year Winckel of Dresden used the nitrous oxid-oxygen analgesia in 50 cases with satisfactory results. 'The apparatus, which con sists of a rubber bag like a pillow, is incon venient, it must be confessed, but this is en tirely subordinate; in abnormally painful labor it is at any rate an extremely important remedy.° (Winckel). But owing to its cost, the impurity of the gases used, the crudeness of the appa ratus, and the fact that it was often given to the stage of asphyxia, nitrous oxide did not become popular at that time.
Dr. J. Clarence Webster of the Presbyterian Hospital, Chicago, was one of the first in Amer ica to use nitrous oxide in obstetrical practice. In 1904 he began to use this anaesthetic in opera tive obstetrics when ether and chloroform were contraindicated. Gradually its use was ex tended to normal cases as a substitute for ether during the delivery of the child. The use of the nitrous oxid-oxygen analgesia during the entire painful stage of labor has been developed during the past few years largely as a result of the constantly increasing demand for painless childbirth.
Von Steinbiichel of Gratz in 1902 suggested the use of scopolamin-morphine analgesia in ob stetrics. Gauss of Freiberg in 1906 made the first report of these drugs given in small gradu ated doses based on a memory test. Because of the semi-sleeping condition of the patient he called this treatment the *Dammerschlaf* (Twilight Sleep). This method has been tried by many physicians with varying degrees of success and failure. Given under the most favorable condition to selected cases the results have been satisfactory in from 70 to 90 per cent of the cases. Most users of scopolamin and morphine are now advocating these drugs only for the first or dilating stage of labor. Some anaesthetic is usually needed for the de livery of the child.
In March 1915, Dr. Webster announced the very satisfactory results which were being ob tained by the obstetrical staff of the Presby terian Hospital, Chicago, from the use of the nitrous oxid-oxygen analgesia during the pain ful stage of labor. This announcement was made only after various members of our staff had tested the method thoroughly on all types of patients and it had been found efficient, easily administered and not too expensive for general adoption. Influenced by the papers of this staff, together with papers from obstet ricians in other cities, this analgesia has been used successfully in several thousand cases dur ing the past two years. It is of considerable significance that of the obstetricians who have used the nitrous oxid-oxygen analgesia long enough to develop a technic not one has ques tioned its value in the management of labor.
While the use of any drug may not be en tirely free from the element of danger, the writer believes that the proper use of any of these drugs or anaesthetizing agents is less danger ous than is the shock of severe pain. With proper care during pregnancy, with the labor skilfully conducted, and with proper facilities for the adaptation of the various anaesthetizing agents to her individual needs, it is possible for the mother of to-day to have a relatively pain less childbirth.