[Measurements of cell nuclei in blood smears from frogs]

In the blood-spread of frog size and extinction of nuclei of erythrocytes, thrombocytes and neutrophile leucocytes with segmental nucleus were investigated. The substance of nucleus was made visible by means of colouring in according to May-Grünwald and the DNA-content in according to Feulgen-reaction. The thickeness of layer and relief of the spread were recorded and measured with a touch-equipment. The nuclei and segments of nucleus, which are flat disks in the dry spread (nuclei of thrombocytes are about 0.75 mum thick), are considered to be rotational ellipsoids in the fluid blood; volume, surface and quantity of DNA are calculated. The erythrocytes have the smallest. the leucocytes the largest quantity of DNA in the nucleus. The concentration of the substance of nucleus and of the DNA increases with the dryness of the spread, to about the sixfold value at the nuclei of thrombocytes.