studies with the hen. Microscopic Study of the Initial Stages of Egg Shell

ABSTRACT During the passage of the egg down the oviduct, the egg shell membrane has essentially three sizes of particles on the outer surface. Membranes from the mid-isthmus have small surface grains, visible only with staining, that range in size from one to ten microns. They occur at approximately 270 per mm.2 increasing to approximately 2700 grains per mm.2 in the posterior isthmus. These grains give a positive reaction for glyoxalbis-(o-hydroxyanil) and a negative reaction for carbonate. The grains are acid soluble and seem loosely attached since they seem to agglomerate during staining. They diminish in number when the egg has progressed into the tubular shell gland and are rarely found once the egg has reached the shell gland. Possibly the grains act as nuclei for the depositions of the secretions of the tubular shell gland. The_particles on the egg shell membrane in the tubular shell gland range from 28 tr ^ 90 mirrnnsTn (iignT*'<*r "Thcca ira ihp mammilla which are enmeshed in the fibers of.the outer shell membrane. They give a positive reaction for carbonate. The mammillae on membranes trom the shell gland range from 60 to 150 microns in diameter. They stain uniformly with nine different histochemical stains, showing a relatively even chemical composition. They grow in size during deposition of shell mineral and eventually touch each other, forming small irregular gaps which become part of the pores of the finished shell