HYDROGEN ION CONCENTRATION IN THE BLOOD 

 OF CERTAIN INSECTS (ORTHOPTERA). 



JOSEPH HALL BODINE, 

 ZOOLOGY LABORATORY, UNIVERSITY OF PENNSYLVANIA. 



Inasmuch as most accurate quantitative results on the hy- 

 drogen ion concentration of blood and body fluids have been 

 largely confined to higher animals it seems highly desirable to 

 extend these observations to lower forms, and especially insects. 

 Since only small amounts of fluids are usually available from 

 single insects, an accurate micro-electrometric method is neces- 

 sary for the successful carrying out of such investigations. A 

 simple micro hydrogen electrode and vessel, particularly designed 

 for this purpose, have been described by the author (Bodine and 

 Fink, i). The present paper contains data obtained by the use 

 of this method for the blood of different species of grasshoppers. 



With the exception of two papers (Bishop, 2; Brecher, 3), all 

 previous work on insect blood seems to have been carried out by 

 means of colorimetric methods (Jameson and Atkins, 4; Crozier, 

 5; Bodine, 6; Glaser, 7). Since the blood of most insects is 

 colored it seems highly desirable that other methods than micro- 

 colorimetric ones be used and especially since the indicator most 

 used in these methods is brom-thymol-blue. The blue-green to 

 % yellow-green color of insect blood seems to introduce an unde- 

 sirable factor in micro-colorimetric methods using this indicator. 

 Results obtained by the use of colorimetric methods by different 

 authors are somewhat variable and it therefore seemed highly 

 desirable to check them by means of an electrometric method. 



In the present investigation different species of grasshoppers, 

 reared under controlled food, temperature and other laboratory 

 conditions, have been used as well as other animals taken from 

 their normal out-of-door environments. Individual studies have 

 been made on the blood of certain species from the day of hatching 

 until death or in other words during their entire life cycle. 

 Blood was taken from the grasshoppers in a variety of ways, by 

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