Miscellaneous. 489 



belongs exclusively to the salt water, Mysis relieta of Loven, one of 

 those extraordinary relics of the glacial period whose presence in 

 some of the great inland lakes of Sweden has lately excited so much 

 interest. I found it in small numbers at Stigersand, below Skreifjeld, 

 in from 8-10 fathoms, just in the corner where a sandbank slopes 

 steeply up from the deeper water beyond. 



" Associated with it, I found numerous examples of a species of 

 Gammarus which at the very first glance differed markedly from the 

 form I had previously noticed, and which seems to be the Gammarus 

 cancelloides of Gerstfeldt, which was first discovered in the Seas of 

 Baikal and of Angara, and which has lately been also found in 

 Sweden, and which Loven likewise considers originally to have 

 belonged to the sea." 



On the Expulsion of the Carbonic Acid from the Blood during 



Respiration. By Dr. Ludwig. 

 As less carbonic acid is present in arterial than in venous blood, the 

 ehmination of this carbonic acid during respiration must be ascribed 

 either to the oxygen or to the tissue of the lungs. For the decision 

 of this question a series of experiments was undertaken, in which this 

 gas was collected from unaltered venous blood, and also from venous 

 blood which had been agitated with air containing oxygen. The 

 blood agitated with oxygen was found to have lost its carbonic acid 

 to such an extent that its amount of this gas was only equal to that 

 contained in arterial blood. There is consequently no reason for 

 regarding the pulmonary tissue as the cause of the evolution of 

 carbonic acid. 



When the unaltered venous blood was left for twenty- four hours in 

 ice-cold water and then analyzed, it appeared that in this case also the 

 amount of carbonic acid was diminished. The same process therefore 

 takes place in blood poor in oxygen as in that which contains oxygen 

 in abundance, but with this difference, that what takes place very 

 completely and in a short time in blood rich in oxygen is effected 

 very gradually in that which is poor in that element. 



To determine whether the evolution of carbonic acid is effected 

 directly by the oxygen, or only by the intervention of the blood- 

 corpuscles, the purest possible serum, which, as is well known, con- 

 tains much carbonic acid, was employed — and, for the sake of com- 

 parison, both unaltered serum and such as had been agitated with 

 oxygen. In these experi^^ents the same quantity of combined 

 carbonic acid was found in every case, and consequently only that 

 portion of the oxygen which has passed into the corpuscles acts in 

 the evolution of carbonic acid. 



As arterial blood may thus be prepared artificially from venous 

 blood, it was natural to try whether the reverse of this process could 

 be effected. This, however, appears to be impossible. For when the 

 oxygen was pumped out of arterial blood and replaced by a quantity 

 of carbonic acid equal to that which usually occurs in venous blood, 

 the amount of combined carbonic acid in the blood could not be 

 increased. Hence it follows that carbonic acid is furnished in the 



