TISSUE RESPIRATION IN INVERTEBRATES 



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YEAR OF STUDY 



Fig, 4. Frequency distribution of types of tissue preparations used in studies on inverte- 

 brate tissue respiration from 1929 through 1959 arranged according to year in which stud- 

 ies were published. Vertical arrow: approximate date when methods for preparation of 

 suspensions and homogenates were first developed. A. Whole organ. B. Pieces (including 

 fragments, strips, teased tissue, zones, parts). C. Slices (including sheets, thin sections). 

 D. Suspension (including cell suspension, ground tissue, mince). E. Homogenate. F. Parti- 

 culate fraction (including mitochondria and microsomes). G. Other fractions (nuclear, su- 

 pernatant). 



