800 Intelligence and Miscellaneotis Articles, 



From the foregoing experiments M. Levol concludes : 

 First. That when ammonia is employed as a reagent, it may hap- 

 pen that the presence of copper, even in large quantity, may escape 

 detection, if the solution also contains protoxide of iron, especially 

 if it be supposed that this oxide is either partially or totally in the 

 state of peroxide. It is not even requisite for this that the operation 

 should be conducted in a close vessel, if the iron preponderates ; 

 because, when once solidified, the pellicle of oxide formed at the 

 upper part of the solution preserves the rest from further oxidize- 

 ment. Thus, in an analysis, or to discover by ammonia copper 

 mixed with iron, it is requisite first to peroxidize the iron entirely. 

 Second. As no suboxide of nickel exists, it cannot occasion the 

 same reaction ; and therefore a new method of distinguishing it 

 from copper results, when in the state of a double ammoniacal salt. 

 This is effected by pouring an excess of solution of a protosalt of 

 iron into the ammoniacal solution, which immediately decolorates it 

 if copper, and not nickel, be held in solution, operating out of the 

 contact of the air. — Annates de Chimie et de Physique, July 1837. 



ON THE GASES CONTAINED IN THE BLOOD, AND ON RESPIRA- 

 TION. BY M. G. MAGNUS. 



M. Magnus remarks that it remains a question whether carbonic 

 acid is formed in the lungs by the oxidizement of a part of the car- 

 bon in the blood by the action of the air, or whether venous blood, 

 when it reaches the organs of respiration, contains carbonic acid 

 ready formed, which is merely separated from it. 



M. Magnus passed hydrogen gas through a solution of potash to 

 deprive the gas of any carbonic acid which it might contain, and when 

 it gave no precipitate with lime wate he passed it into the blood of a 

 healthy man ; the gas afterwards made to go through lime water 

 o-ave a plentiful precipitate of carbonate of lime. Azotic gas simi- 

 larly employed produced a like effect; and M. Magnus concludes, 

 from these experiments, that carbonic acid exists ready formed in the 

 blood, and consequently that it is not formed in the lungs. Car- 

 bonic acid was also separated from blood by means of the air-pump. 



By using Liebig's apparatus M. Magnus found that blood contained 

 about one- fifth of its volume of carbonic acid gas, and when it had 

 been kept 24 hours, without emitting any bad smell, the quantity 

 was larger. The results were confirmed by employing atmospheric 

 air instead of hydrogen gas. 



M. Magnus then ascertained the nature and proportions of all the 

 gaseous contents of the blood. He found that 100 volumes of the 

 arterial blood of a horse yielded 



Carbonic acid gas 4*32 vols. 



Oxygen r52 „ 



Azote 2- ,, 



Total 7-84 vols. 

 The venous blood of the same horse, drawn 4 days afterwards, gave 



