THE USE OF A PLANIMETER IN VOLUME STUDIES OF EARLY EMBRYOS

Abstract

A method of determining the volume of early embryos is described. Serial sections of the egg or embryo are traced on suitable paper at known magnifications and the tracings are measured with a planimeter. A formula is presented which, by the use of the values for the area of the tracings, the thickness of the sections, and the magnification, gives the volume of the specimen. The accuracy of the method is apparently great, particularly for relative volumes, but accuracy for absolute values is somewhat less because of the necessity of considering each section as a section of a cylinder. Data resulting from the use of this technique will be published elsewhere.