458 EFFECT OF TEMPERATURE UPON FACET NUMBER 



phenomenon has a negative temperature coefficient. Experiments demonstrate 

 a decrease in rate of nerve conduction with increase in viscosity at a constant 

 temperature. 



Balls maintains that the more rapid accumulation at higher temperatures of 

 the waste products retards the primary reaction. While these products are 

 formed at the lower temperatures, they are disposed of at a rate sufficient to pre- 

 vent the checking of the primary reaction. At high temperatures they are formed 

 more rapidly than they can be carried away. Their experimental removal, by 

 dilution of the surrounding medium, raised the optimum of growth for the sore- 

 shin fungus considerably. 



Coagulation of proteins, which has been advanced as an explana- 

 tion of death at the higher temperatures, might be suspected of 

 producing a retardation in rate at the submaximal temperatures. 



Straight Line Physiological Reaction Curves. 



Most physiologists have given up van't Hoff's formula as too in- 

 accurate to have any practical value. They have abundantly dem- 

 onstrated the metabolic rate relations to be a linear rather than an ex- 

 ponential function of the temperature. 



LoeVs Hypothesis of Secondary Factors. 



Loeb has recently explained the straight line character of the rate 

 curves to be due to the flattening out of an exponential curve by sec- 

 ondary factors. He shows that the "rate of life" of the imago of 

 Drosophila may be plotted as an exponential curve, and that there 

 is no falling off at the higher temperatures. 



The criticism can be made, however, that an examination of his 

 rates above 31° demonstrates clearly the presence of secondary factors 

 that would tend to convert a straight line curve into an exponential 

 curve. 



A consideration of these various explanations of straight line curves 

 and optima is now in order in light of the present work. 



