564 TISSUE RESPIRATION 



ground up and treated with alcohol or, better, with acetone, 

 and quickly dried in vacuo over sulphuric acid, a tissue 

 powder may be obtained which is capable of taking up no 

 inconsiderable amount of oxygen and of producing 

 carbonic acid. 



The tissue respiration is deteriorated by poisons like 

 prussic acid, oxalates and fluoride of sodium; is, on the 

 other hand, increased by slight alkaline concentrations. In- 

 troduction of glucose, citric acid, malic acid or fumaric acid 

 increases very decidedly the tissue gas interchange at times. 

 These substances moreover are capable of oxidizing ethyl 

 alcohol to aldehyde and the latter into acetic acid, and of 

 converting succinic acid into malic acid (COOH.HC 2 .CH 2 . 

 COOH-^COOH.CH (OH) .CH 2 .COOH) , 17 



Experiments along similar lines have been conducted by 

 Olav Hanssen in F. Hofmeister's laboratory. 18 Ground-up 

 tissue was kept in agitation in flasks at body temperature, 

 oxygen being conducted through the medium ; and the gas 

 passing off was tested for its content of carbonic acid. The 

 experiments of Harden and Maclean tend in the same di- 

 rection, indicating that isolated tissue under the conditions 

 described do not produce any more carbonic acid from sugar 

 in an atmosphere of oxygen than in a nitrogen or hydrogen 

 atmosphere. 19 Buytendyk in turn sealed the tissue in a 

 measured amount of special salt solution and tested the 

 diminution of oxygen content of the latter ; under these con- 

 ditions, too, the cardinal respiration could be readily distin- 

 guished from the accessory respiration. 20 Finally Lussana 

 performed the same sort of experiments under more nearly 



17 F. Battelli and L. Stern, Biochem. Zeitschr., 21, 488, 1909; 28, 145, 1910; 

 SO, 172, 1910; 31, 478, 1911; 33, 315, 1911; 36, 114, 1911; Ergebn. d. Physiol., 

 12, 215-216, 1912. 



18 O. Hanssen (F. Hofmeister's Lab., Strassburg), Biochem. Zeitschr., 22, 

 433, 1909. 



"A. Harden and H. Maclean, Jour, of Physiol., 43, 34, 1911. 

 30 F. J. J. Buytendyk (Utrecht), VIII Int. Physiol. Kongr., Vienna, Sept. 

 27-30, 1910. 



