CHEMICAL PHYSIOLOGY. 99 



tween the absorption of oxygen and formation of carbonic 

 anhydride in human respiration. J. Haldane and J. L. 

 Smith [Jour. Pathol, and B arteriole i. 318) have performed 

 experiments on Merkel's plan, which were found to lend 

 no support to Brown-Sequard's hypothesis, that air con- 

 tains a special organic poison. These results confirm the 

 previous statement by the authors, that the only toxic 

 substance in expired air is carbonic anhydride. Respira- 

 tion in fishes has been investigated by C. Duncan and 

 F. Hoppe-Seyler [Zeit. pJiysiol. Chem., xvii. 165) ; the 

 influence of light on gaseous interchange by C. A. Ewald 

 (Jour. Physiol., xiii. 84), who finds the influence is not 

 appreciable if muscular action is eliminated ; the influence 

 of fatiguing muscular work on the respiratory interchange 

 by A. Loewy (Pfliiger's Archiv, xlix. 405). He finds that 

 when work is excessive the normal ratio between intake 

 and output is upset, and the respiratory quotient rises : 

 and that during fatigue more muscular activity is ex- 

 pended in doing a certain amount of work than when 

 the muscle is fresh. Another paper may be here alluded 

 to, though it does not treat directly on respiration ; it 

 is on the action of nitrites on muscular tissue ; the 

 authors are J. T. Cash and W. R. Dunstan (Proc. Roy. 

 Soc, lii. 91); the full paper has since appeared in the 

 Phil Trans, (vol. clxxxiv., 1893, P- 5°5)< anc ^ though it 

 treats more especially of a pharmacological subject, will 

 be found to present many points of interest to physiologists 

 also. 



Gaseous tension in the blood and serum of peptonised 

 animals is treated of by V. Grandis (Real. Accad. Line, vii., 

 ii. 471) ; the gaseous tension of carbonic anhydride is 

 increased in these animals in the venous blood. The 

 quantity of free carbonic anhydride in the serum is 

 slightly increased ; that of combined carbonic anhydride 

 considerably diminished. The blood gases during anaes- 

 thesia have been analysed by Oliver and Garrett (Brit. 

 Med. Jour., 1893, n - 683); an excess of nitrogen was 

 found. 



Blood and Pigments. — The coagulation of the blood 



