VOL. LXIX.] ' PHILOSOPHICAL TRANSACTIONS. 527 



ling animals that breathed it. Dr. Priestley, to whom we are much indebted for 

 many discoveries and observations relating to inflammable air, made in conse- 

 quence of Mr. Cavendish's excellent paper on that subject, assures us, that in- 

 flammable air causes the death of animals as readily as fixed air, and that animals 

 die convulsed in it. The doctor adds, that water absorbed about one quarter of 

 the inflammable air shaken in it, after which a mouse lived in it as long as it 

 would have lived in an equal quantity of common air. This air breathed by the 

 mouse was still inflammable, though not so much as before. Mr. Scheel on the 

 contrary asserts, that inflammable air not only does not kill the animals who 

 breathe it, but that it is even good and innocent air. He relates some experi- 

 ments to which it seems that nothing can be opposed, and they appear to con- 

 tradict Dr. Priestley's observations. Mr. Scheel has breathed inflammable air 

 contained in a bladder, without receiving any hurt. Seeing then that the expe- 

 riments of these celebrated persons contradicted each other, I began to suspect 

 says the Abbe) that they might possibly be all true ; and that their so contra- 

 dictory effects might be owing to some circumstance not yet attended to. 



In order to follow some method in my researches about a point so delicate, and 

 which so nearly interests human life, I first of all thought of assuring myself, 

 whether animals could breathe inflammable air with impunity, when the receivers 

 that contained it were immersed in quicksilver. To this end, I introduced in- 

 flammable air, extracted both from zinc and iron, by means of the vitriolic acid, 

 into various tubes filled with quicksilver, in which the air entered pretty free 

 from moisture. I then introduced various birds into those tubes, and observed 

 that they died in a few minutes time, but without any apparent sign of convul- 

 sions. These experiments, hsving been often repeated, were constantly attended 

 with the same event. Being assured, beyond any doubt, that the inflammable 

 air obtained from zinc or iron, and made to pass through quicksilver, was fatal 

 to animals ; I next wished to observe, whether it retained the same properties 

 when it had passed through water ; in which case the volatile sulphurous acid, 

 or other vapour, is absorbed by the water ; but, on trying the experiments, I 

 found that the birds died under these circumstances as under the others, though 

 not quite so soon, showing also some signs of convulsion. I introduced some 

 of this same air, that had passed through water, into a glass tube full of quick- 

 silver, by a method which makes the air lose all its moisture. The birds died in 



which had been published in Italian in 1767, under the title of Ricerche sopra il Veleno deUa Vipera) 

 the Abbe treats not only of the poison of the viper, but of the American poisons, of the Lauro- 

 cerasus, &c. correcting many errors of former writers on diese subjects, and presenting many new 

 and interesting experiments relative to the operation of animal and vegetable poisons on tlie living 

 body. This work, moreover, contains observations on the structure of the nerves, with experiments 

 on their reproduction, and a description of a new canal of the eye. 



