WALLACE O. FENN 



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peratures below 15° where the reactions were continued for 24 and 48 

 hours; and it has seemed justifiable, in calculating the value of Qio, to 

 discount these figures on account of secondary changes which might 

 occur in such prolonged experiments. If this is done, the values for 

 the temperature coefficient are 1.7 and 1.3 respectively. This bears 

 out the qualitative conclusion arrived at from mere inspection of the 

 curves in Fig. 1 that the temperature coefficient of the reaction re- 

 sulting in injury to the cells was lower than that for the process of 

 phagocytosis itself. 



Fig. 4. Logarithms of the reciprocals of the times necessary to ingest the maxi- 

 mum number of bacteria (ordinates) plotted against temperature (abscissae). 

 Data taken from the same two experiments of Madsen and Watabiki as for the 

 graphs of Figs. 2 (lower) and 3 (upper). Slope of the graph is proportional to 

 the logarithm of the value of ^lo for that interval. Values calculated from the 

 slopes of the solid lines are inserted. This is regarded as the temperature coeffi- 

 cient of the lethal reaction resulting in the death of the cell and cessation of phago- 

 cytosis. 3.75 and 2.5 have been added to the values for the upper and lower 

 curves respectively for convenience in plotting. 



Loeb (4) and Osterhout (5) have developed the conception of 

 catenary reactions as applied to biological reactions, and the latter 

 has recently discussed temperature coefficients irom this point of view. 



