Factors Influencing the Specific Gravity of Insect Haemolymph

Abstract

The physiochemical properties of the blood of an animal are maintained in a close equilibrium conducive to the normal functioning of the organism. Disturbances in the physiological functian may result in characteristic changes in the blood. For example, the specific gravity of normal human blood, which averages about 1.060, may vary with age, sex, nutritive condition, and disease (Hawk, Oser. and Summerson, 1947). The reaction of blood to metabolic and pathological conditions is recognized by the medical profession as a valuable aid in diagnosis (Scudder, 1939). Changes have been shown in the specific gravity of human blood in pregnancy and cancer (Polowe, 1932; 1934). It has also been shown that haemorrhage is accompanied by a decline in the specific gravity (Richet, Brodin, and Saint-Girons, 19 18).