178 Papers from the Department of Marine Biology. 



substance is formed under the influence of excessive heat, its rate of 

 formation being commensurate with the metabolism of the tissues. 

 It is easy to see how an acid of this sort might be eliminated and the 

 rate gradually restored when the animal is replaced in normal sea- 

 water, whereas if an enzyme were destroyed it might not so readily 

 be replaced. 



In any event, one or the other of the above-mentioned hypotheses 

 seems more in accord with the facts than does Winterstein's asphyxia- 

 tion theory, or the theory that death from heat is due to coagulation 

 of proteid substances. Death occurs at too low a temperature for 

 coagulation in most if not all proteids; and when killed the animals 

 are fully relaxed, as shown by Harvey. Also, coagulated proteins could 

 not readily be eliminated when the animal was restored to water at 

 normal temperature, coagulation being a practically non-reveisible 

 process. 



SUMMARY. 



It seems possible that death from high temperature may be due to 

 the accumulation of acid (possibly H 2 CO 3 ) in the tissues, the rate of 

 formation of this acid being related to the rate of metabolism of the 

 tissues. Thus animals of the same class having a high rate of metabo- 

 lism, as measured by oxygen consumption, are more sensitive to heat 

 and to COo than are those having a low rate of metabolism. 



LITERATURE CITED. 



BLACKMAN, F. F. 1905. Annals of Botany, 19, p. 281. 



HARVEY, E. N. 1911. Carnegie Inst. Wash. Pub. 132, p. 27. 



HENZE, M. 1910. Biochem. Zeitschrift, 26, p. 266. 



McCLENDON. J. F. 1917. Year Book Carnegie Institution of Washington for 1917. 



MAYER, A. G. 1908. Carnegie Inst. Wash. Pub. 102, p. 115. 



SACHS, JULIUS. 1865. Handbuch der Exper. Physiologic, p. 52. 



WINKLER, L. W. 1888. vide Treadwell and Hall, 1905, Analytical Chemistry, 2, p. 574. 



WINTERSTEIN, H. 1905. Zeitsch. fiir Allgemeinen Physiologic, 5, p. 323. 



