226 ANNUAL OF SCIENTIFIC DISCOVERY. 



The coca leaf has been subjected to chemical analysis by M. Nie- 

 mann, a pupil of Professor Wohler, of Gottingen, who succeeded in 

 insulating from it a peculiar alkaloid, to which he has given the name 

 of " cocaine." 



POISONOUS EFFECTS OF CARBONIC OXIDE. 



Dr. Letherby, of the London Hospital, who has recently devoted 

 much attention to physiological action of carbonic oxide, states that 

 he has ascertained that this gas is so deadly in its action that air con- 

 taining only 0.5 per cent, of it will kill small birds in about three 

 minutes ; and that a mixture containing one per cent, of the gas will 

 kill in about half this time. An atmosphere having two per cent of 

 the gas will render a guinea-pig insensible in two minutes ; and in all 

 these cases the effects are the same. The animals show no sign of 

 pain ; they fall insensible, and either die at once with a slight flutter, 

 hardly amounting to convulsion, or they gradually sleep away as if in 

 profound coma. The post-mortem appearances are not very striking ; 

 the blood is a little redder than usual, the auricles are somewhat 

 gorged with blood, and the brain is a little congested. In birds there 

 is nearly always effusion of blood in the brain, and it may be seen 

 through the transparent calvaria by merely stripping off the scalp 

 after death. 



Accident has also demonstrated how injurious the gas is even to 

 the human subject. For many years past attempts have been made 

 to promote the use of water-gas as an agent of illuinmatidh. The gas 

 sometimes contains as much as thirty-four per cent, of carbonic oxide. 

 It is obtained by passing steam over red-hot charcoal ; and as the 

 steam is decomposed by the ignited carbon, the hydrogen is set free, 

 and carbonic oxide, with carbonic acid, is produced. Patents for this 

 process of manufacturing gas date as far back as the year 1810, and 

 they have at various times been put into operation into this country 

 and on the Continent. Sellique. in 1840, obtained permission to use 

 the gas in the towns of Dijon, Strasburg, Antwerp, and two of the 

 faubourgs of Paris and Lyons. At Strasburg an accident occurred 

 which put a stop to its use. The gas escaped from the pipes into a 

 baker's shop, and was fatal to several persons ; and not long after an 

 aeronaut, named Delcourt, incautiously used the gas for inflating his 

 balloon. He was made insensible in the car, and those who approached 

 the balloon to give him assistance fainted and fell likewise. The use 

 of the gas has, therefore, been interdicted on the Continent. 



CARBONIC ACID AS AN ANESTHETIC. 



Dr. Ozonam has recently detailed to the French Academy his ex- 

 periments on the above subject. After forty trials with delicate ani- 

 mals, whose sleep he had prolonged for one or two hours at a time 

 without accident, he operated upon a human subject suffering from a 

 deep abscess in the thigh. He begun by administering a mixture of 

 three parts of carbonic acid and one of common air contained in a 

 caoutchouc bag, and furnished with a long tube, terminating in an 

 enlarged opening, capable of receiving the mouth and nose. This 

 was applied so loosely that the patient could respire air as well as the 



