PREFACE 



May we introduce this work with an explan- 

 ation of its general organization and its 

 contents? In Section 1, Introduction, we have 

 traced the historical development of the study 

 of invertebrate tissue respiration from its be- 

 ginnings late in the nineteenth century up to the 

 present time. In doing so, we have placed par- 

 ticular emphasis on the influence exerted by 

 new apparatus and techniques. We have pre- 

 sented graphically the distribution of studies 

 among various phyla and classes of inverte- 

 brate animals. From this initial survey it 

 should be apparent to the reader how rapidly 

 the field of invertebrate tissue respiration is 

 developing and how broad and active it remains 

 today. 



While scanning the literature, we found a 

 wealth of usable data. Section 2, the principal 

 portion of this volume, contains these data, ar- 

 ranged to indicate the variation in respiratory 

 rate with animal and type of tissue, with amount 

 of tissue, with concentration and type of sub- 

 strate, with sex of the animal, with season of 

 the year in which the assay was made, and with 

 many other factors. 



Owing to such an abundance of material, we 

 found it necessary to limit our coverage as re- 

 gards specific enzymes and enzyme systems. 

 Thus, while Section 2 includes many examples 

 of endogenous respiration, for the most part it 

 omits reference to enzymes other than those 

 of the citric acid cycle and the electron trans- 

 port system. Furthermore, whereas data from 

 an original paper containing few entries usu- 

 ally appear in their entirety, those from a 

 more extensive study have been selected (1) to 

 afford representative sampling and (2) to illus- 

 trate principles and hypotheses. Footnote su- 

 perscript "t" appears after any bibliographi- 

 cal reference in Section 2 if there are more 

 data in an original paper than appear in Sec- 

 tion 2. 



Although the data contained in Section 2 refer 



to tissues derived from invertebrates of many 

 species, the section includes no information 

 regarding the respiration of protozoans, nor 

 does it deal with respiratory rates of sperms 

 and of fertilized or unfertilized eggs. 



Many types of tissue preparations are men- 

 tioned in Section 2. These include whole organs, 

 slices, teased tissues, minces, cell suspensions, 

 homogenates, and fractions (nuclear fraction, 

 mitochondria, microsomes, or soluble fraction). 



The arrangement of data in Section 2 is phy- 

 logenetic, according to the classification ad- 

 vocated by Hyman (1940-1959, vol. 1). Since 

 phylum and class are the categories most fre- 

 quently selected for mention by biochemists 

 and experimental biologists, we have not in- 

 cluded references to other higher categories. 

 The valid scientific name of each animal and 

 at least one of its common names appear in 

 this section. In a Systematic Index (see Section 

 9) a scientific name, if no longer valid, can be 

 traced to the presently correct one. 



In order to tabulate the data on invertebrate 

 tissue respiration, we found it necessary to 

 convert figoires on oxygen uptake from the 

 units employed by a given investigator into one 

 of several selected expressions of metabolic 

 rate. Thus in Section 2, data appear as the 

 mean number of microliters of oxygen per hour 

 per milligram of nitrogen, protein, wet weight, 

 or dry weight, or alternatively as '^^ enzymatic 

 activity," with footnotes indicating the units in 

 which enzymatic activity is given. The complete 

 list of footnotes, which are arranged in an ar- 

 bitrary, not sequential, order, is repeated on 

 each page of Section 2, although a reference 

 to every footnote may not appear on every page 

 within the body of the table. 



Wherever we have converted our units, we 

 have indicated this fact by the footnote super- 

 script "a" after the data. When possible, we 

 have changed all expressions for concentration 

 of reactants into molarity and have noted this 



