C. S. Shaffner

Pulmonary ventilation in a population of hatching chick embryos

Synopsis Two experiments were made to study pulmonary ventilation in the hatching chick embryo with particular reference to the part played by the air cell. The hatchability of embryos without access to the air cell was the same as for normally positioned embryos. The lungs of about 35 per cent of the normally hatching embryos were inflated in the air cell, but 65 per cent were inflated after breathing atmospheric air. The shell was cracked but not pipped before the outer membrane was penetrated. Comparisons between different groups of normally and abnormally positioned unhatched embryos revealed that the air cell had an insignificant respiratory value, but that the mechanical advantages of the large end seemed apparent. The time relationships between lung inflation, inner membrane perforation, pipping, yolk sac retraction, outer membrane perforation, lung discoloration and hatchability were studied. Equations were derived for the regression on time of each of the seven variables studied. Statistically in...

Oviductal glycogen content of laying and nonlaying hens and of estradiol stimulated pullets.

Summary Administration of 17β-estradiol to immature chicks elicited a 2-3-fold increase in oviducal glycogen. The laying hen had an oviducal glycogen content (μg/unit of DNA) similar to the immature bird treated with estrogen, while the oviducal glycogen concentration of the nonlayers was similar to the immature controls. The elevated oviducal glycogen of the laying hen is probably a result of estrogen secretion.