SOME RELATIONS BETWEEN RHEOTAXIS AND THE 

 RATE OF CARBON DIOXIDE PRODUCTION 



OF ISOPODS 



W. C. ALLEE 



Thompson Biological Laboratory, Williams College 



AND 



SHIRO TASHIRO 



Laboratory of Biochemistry and Pharmacology, the University of Chicago 



For several years one of us has been working upon an analysis 

 of the rheotactic reaction of the isopod, Asellus communis, Say. 

 In the course of this work it became evident that certain con- 

 ditions known to affect animal metabolism likewise regularly 

 affected the rheotactic reaction of isopods. Thus it was found 

 that low oxygen tension, high carbon dioxide tension, chlore- 

 tone, potassium cyanide, lowered temperature, sudden extreme 

 increase of temperature, starvation, and fatigue decreased the 

 percentage of positive rheotactic responses given. On the other 

 hand caffein, increased oyxgen tension, and a gradual increase 

 of temperature had the opposite effect. (Allee, '12, '13.) 



When the rate of metabolism of isopods was determined by 

 their resistance to potassium cyanide (Child, '13, '13a; Allee, 

 '14; also page 206.) isopods giving a high percentage of positive 

 rheotactic responses in a circular current had the highest rate 

 of metabolism. Those with a high per cent, of negative re- 

 sponses were second, while those with a low positive response 

 and with either the negative or indefinite reaction dominating 

 had the lowest rate of metabolism. 



For a number of years the other of us has been working upon 

 a method for determining with analytical accuracy the minute 

 amounts of carbon dioxide given off in the metabolism of nerve 

 fibers. (Tashiro, '13, '13a, '14.) The apparatus devised will 

 detect and measure with accuracy 0.000,000,1 gram of carbon 

 dioxide. 



For those who are not familiar with the new method for 

 determining carbon dioxide we may say that the quantitative 

 method depends upon determining the minimum amount of gas 



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