154 MATERIA MEDIC A AND THERAPEUTICS. 



of consciousness and of natural breathing occurs in thirty to 

 sixty seconds, with disappearance of all the urgent symptoms. 

 It is clear that asphyxia is carried into the second stage that 

 of respiratory excitement, but not beyond, neither the move- 

 ments of the chest nor the action of the heart being arrested. 

 But even if these untoward results should occur, resuscitation 

 is easy by means of artificial respiration; it is said even after 

 five minutes in the case of rabbits. No attempt to carry the 

 asphyxia beyond the second stage is permissible in man. 



Nitrous oxide gas is extensively used to produce anaesthesia 

 during operations lasting but one minute or less, and especially 

 by dental surgeons during the extraction of teeth, destruction 

 of the nerve, etc. It must always be given pure, by the 

 arrangement above described in the hands of a skilled anaesthe- 

 tist. The moment for operating is best indicated by stertorous 

 breathing and twitching of the muscles. Persons with dis- 

 eased vessels, such as the subjects of chronic Bright's disease, 

 ought not to take this anaesthetic, which produces (like all 

 asphyxiating agents) a great and sudden rise of the arterial 

 pressure, likely to cause rupture within the brain. 



BICHLORIDE OF ETHIDENE. (Not Officinal) 



Source. Obtained in the manufacture of chloral. 



Characters. A colourless volatile liquid, with the odour 

 and taste of chloroform. Specific gravity, T20. Readily 

 soluble in ether, chloroform, and alcohol; with difficulty in 

 water. 



ACTION AND USES. 



Bichloride of ethidene is a general ansesthetic, supposed 

 to occupy a position somewhat between ether and chloroform, 

 but depressing the heart more than the latter. It is a very safe 

 anaesthetic in some animals, but, like all its allies, occasionally 

 causes death in man. About 4 n.dr. in the form of vapour are 

 required for an adult. 



BROMIPUM. BROMIDE OF ETHYL. 

 HYDROBROMIC ETHER. C 2 H 5 Br. (Not Officinal.) 



Source. Made by adding Bromine to a mixture of Phos- 

 phorus and Absolute Alcohol, and distilling. oCaHgO -f- PBr 5 

 (bromide of phosphorus) = 5Cyi 5 Br + H 3 P0 4 + H 2 0. 



Characters. A colourless liquid with a powerful fragrant 

 odour, and a hot sweetish taste. Very volatile ; specific gravity, 



