Studies on egg shells. II.—A method for marking and counting pores

Abstract A method has been developed for marking the pores in egg shells by immersing them in concentrated nitric acid for very short periods of time. This makes the pores easily visible under the microscope, and counting can then be done by a statistical method. Not only is the total number of pores determined, but also a frequency distribution is obtained which indicates that the pores are not distributed at random.