434 



SCIENCE. 



true deviation, we have from the above constants 



Li — D T D y\ . 



144— t 



In the table given by Mr. Casamajor the quantities 

 which t was equal to was given, so that by a simple cal- 

 culation it became read ly possible to determine the value 

 of the true deviation. The table was based on the 

 much larger one of Clergets. 



The fourth paper of the evening was by Mr. A. H. 

 Elliot and it consisted of a description of " A New 

 Form of Apparatus for the Analyses of Gases." It was 

 very severely criticised by Dr. Endeman as being de- 

 cidedly inferior to the more complicated forms devised 

 by Professor Hempel. M. B. 



THE SUCCESSFUL ADMINISTRATION OF NI- 

 TROUS OXIDE AS AN ANAESTHETIC FOR 

 DENTAL AND SURGICAL OPERATIONS.* 

 Dr. E. P. Howland, Washington, D. C. 



The successful administration of nitrous oxide consists 

 in administering it to patients in such a manner that 

 during operations they will not suffer pain, and that they 

 will be in such a condit'on that the dentist and surgeon 

 can successfully perform the operation and afterwards 

 that the patients are found not to be injured by its admin- 

 istration. The first requisite for success is that the 

 nitrous oxide should not have more than one per cent of 

 pure oxygen or three per cent of atmospheric air, and 

 that it should be perfectly free from all other gases or 

 vapors. Nitrous oxide with two per cent or more of 

 pure oxygen or five per cent or more of atmospheric air, 

 will not produce perfect anaesthesia and the patient wi'l 

 feel the pain of the operation and pronounce the gas a 

 failure. The adding of one per cent of pure oxygen to 

 nitrous oxide has the benefit of partially oxygenating the 

 blood and in a measure preventing the spasmodic action 

 of the muscles and at the same time produce satisfactory 

 anaesthesia. According to experiments made in France 

 by P. Bert, ten per cent of oxygen or fifty per 

 cent of atmospheric air can be added to nitrous 

 oxide to oxygenate the blood, and at the same 

 time produce perfect anaesthesia if it is breathed in a 

 chamber under a pressure of two atmospheres. A certain 

 amount of nitrous oxide taken into the lungs is necessary 

 to produce insensibility, and it can be diluted with any- 

 innocuous gas and still produce anaesthesia, provided this 

 amount is inhaled in the given time. Under pressure in 

 a chamber more gas is breathed in a given time, as the 

 nitrous oxide is condensed the same as the air in the 

 chamber and under a pressure of two atmospheres, two 

 volumes of nitrous oxide would be condensed into one 

 volume, so that the nitrous oxide could be diluted with 

 equal measures of atmospheric air and still the quantity 

 of nitrous oxide inhaled would be the same as if breathed 

 ordinarily and the quan'ity of oxygen breathed sufficient 

 to arterialize the blood. Rapid breathing of nitrous 

 oxide produces quick anaesthesia, but nothing is gained 

 by it in practice. It is very difficult to produce anaesthe- 

 sia with nitrous oxide at high elevations above the ocean, 

 because the low pressure of the atmosphere allows the 

 gas to expand so that a less quantity is taken into the 

 lungs in a given time than is required to produce insen- 

 sibility. Valve inhalers have generally proved a failure, 

 because they admit atmospheric air with the gas in suf- 

 ficient quantity to to prevent perfect anaesthesia. As 

 near as I can ascertain, more than one-half of all the 

 dentists of the United States who have used nitrous oxide 

 have abandoned its use on account of want of success in 

 producing satisfactory insensibility and thereby injuring 

 instead of benefiting their practice. One cause of fail- 

 ure is the unskillful administration of the gas in allowing 



* Read before the A. A. A. S., Cincinnati, 1881. 



air to be inhaled with it, by not having the lips closed 

 tight around the inhaler, and other causes ; not using the 

 nose as a valve for expiration exactly at the right time ; 

 not stopping the administration at the point of greatest 

 anaesthesia and not having sufficient self-possession un- 

 der all circumstances and emergencies to know just what 

 to do and when to do it. But the greatest cause is the 

 failure of producing perfect anaesthesia from the mixture 

 of atmospheric air in the nitrous oxide that has been kept 

 in a gasometer over water for a few days. The gas be- 

 comes mixed with air through the medium of the water 

 and defective gasometers and cocks. The trouble and 

 cost of making lresh gas every few days has caused the 

 great abandonment of its use. Skillful administrators, 

 who have a large practice and make fresh gas before 

 deteriorated by air, are making nitrous oxide a success. 

 Other dentists can make gas a success by obtaining it 

 condensed in cylinders, when the gas will keep unadul- 

 terated and unchanged for years. The only drawback 

 to a paying success is the present great cost of the con- 

 densed gas, which in the small cylinders amounts to 

 about thirty-five cents for each administration, when the 

 gas can be made in the dentists' laboratory for about 

 three and a half cents for each administration. An 

 apparatus can now be obtained that enables each dentist 

 to make and condense his own gas and keep it for any 

 length of time. Physicians and surgeons do not use 

 nitrous oxide on account of the trouble and cost of mak- 

 ing and keeping it, and the greater amount of practice 

 and skill required in its successful administration than with 

 the more dangerous ether and chloroform. Nitrous oxide 

 requires a costly apparatus to manufacture it, and bulky 

 receptacles to hold and administer it from, and the gas 

 is for sale in but two places in the United States, while 

 ether and chloroform can be carried in a bottle in th; 

 pocket and purchased at every drug store in the land. 

 Nitrous oxide can be administered with almost absolute 

 safety, while ether and chloroform can point to their 

 victims in every city and hospital. Money, labor and 

 skill can make nitrous oxide successful with both dentist 

 and surgeon, and taking into account the value of human 

 life, nitrcus oxide should stand at the head of all 

 anaesthetics, and its practical use be encouraged instead 

 of eiher and chloroform. 1 



I have administered nitrous oxide in over thirty 

 thousand cases for dental and surgical operations, and 

 have had uniform success. I have never had a case of 

 injury from lung or heart disease, but in many cases of 

 throat and lung diseases a marked and permanent im- 

 provement. I have kept a .large number of patients per- 

 fectly anaesthetic for surgical operations from five to 

 thirty-five minutes, and the pulse during these operations 

 has been nearly uniform and full. The success cf pro- 

 longed operations consists in first producing perfect 

 anaesthesia and then breathing air to arterialize the blood 

 and before consciousness returns again breathing nitrous 

 oxide, the necessary iutervals varying in different patients 

 from one-fourth to one-half minute. The average length 

 of time occupied in dental operations from the first com- 

 mencement of breathing the gas till return of conscious- 

 ness has been two minutes. To encourage and make 

 nitious oxide a greater success in the future, the dental 

 and medical colleges should employ successful operators 

 to lecture and instruct graduates so that the particular 

 knowledge and skill acquired by them in practice can be 

 learned by others. 



On October 17 next, fifty years will have elapsed since 

 Prof. Bunsen, the eminent chemist, received his doctor's 

 diploma from Gottingen University. He, however, intend* 

 to absent himself from Heidelberg on the da} - in question, 

 in order to avoid all congratulations and speech-making. 



Mr. W. H. M. Christie, F. R. S., First Assistant at 

 Greenwich Observatory, has been appointed Astronomer 

 Royal, in succession to Sir George Airy, who retires after 

 holding the office for nearly half-a-century. 



