Variations in the Blood Cell Volume of Individual Fish

Abstract

THE purpose of the research described in the following account was to determine whether large variations in the blood of different fishes have their counterpart in that of the same individual at different times, using for this purpose the cell volume per cent as determined in the Van Allen (1925) hematocrit tube. Evidence of high variability in fish blood has been presented by many workers (Baudin, 1936; Kokubo, 1927; Schlicher, 1927; Zunz, 1933; Black, 1940; etc.), and I have found variations in the red-cell count of individual fish ranging from less than one to more than four million cells per cubic millimeter. The hematocrit method affords a convenient and reliable way of determining variations in cell volume regardless of the extent to which this volume is determined by size or number of cells present. I am indebted to Dr. H. U. Sverdrup, formerly Director of the Scripps Institution of Oceanography, for the privileges of the Institution during this research, and to other members of the staff for many courtesies shown me.