«iIENTIFIC NEWS. ^|^ 



gen directly from the atmosphere. The experiments of 

 Messrs. von H. and P. have gone farther. Seven tenches 

 were placed under a jar filled with river water, containing 

 4000 cent, cub. [243*6 cub. inch.]. After living in it eight 

 hours and a half, the analysis of the air still foand in the 

 water showed, that the fishes had absorbed in this time 

 145*4 [8*85 cub. in.] of oxigen, and 57*6 .[3'5] of nitrogen, 

 and that 132 [8] of carbonic acid had been produced. 



In water deprived of air the fishes were uneasy, and in Effects of dif- 

 about twenty minutes fell motionless to the bottom. In otHhei^^**" 

 pure oxigen they appeared to respire eagerly, and spread 

 their gills more. In nitrogen and bidrogen they kept their 

 gills closed, seemed to dread the contact of these gasses, 

 and died soon after they were put into the water containing 

 them. Carbonic acid too kilU them in a few minutes. 

 But it is not by their gills alone that fishes absorb oxigen 

 and nitrogen, the whole surface of their bodies has the fa^ 

 culty of acting on these gasses. After the fishes were taken 

 out of the water containing the deleterious gasses, a small 

 portion of carbonic acid was found in it, exhaled probably 

 from their bodies. 



Mr. Provencal has also made some experiments on the Respiration of 

 respiration of mammalia after the eighth pair of nerves ^^"'^V^. , 

 had been divided. The animals gradually absorbed less nerves was di- 

 oxigen, and produced less carbonic acid, after the operation. ^^^^' 

 At first their respiration was not apparently weakened ; but 

 it soon became feeble; and at length ceased altogether: 

 probably from the cessation of the mechanical functions of 

 the thorax. The heat of the animal diminished soon after 

 the division of the nerves, and proportionably with the re- » 

 spiration. '' '*''■' '•'•-■-•■'-"- -•-■— '^'"^■■■'. '' "'^ ' ■''^■■: 



With the functions of the airbladder of fishes we arc not AirbUdderof 

 yet well acquainted. In some it has a duct communicating ^** 

 with the stomach. In others this duct is wanting, and it 

 contains a peculiar organ of a red colour, and a laminated 

 structure. In some both this organ ^nd the duct are found, 

 and in a few this bladder has muscl&s. The air contained 

 in this bladder is a mixture of oxigen and nitrogen, the 

 former being in greater quantity in proportion to the depth 

 ^t which the fish Uvea in the water, Its absence does not 



appear 



