The air space and embryonic respiration

Abstract

Synopsis Blocking the respiratory exchange through the shell over the air space by coating the shell with paraffin was attended by a sharp decrease in the oxygen content and a moderate increase in the carbon dioxide content of the air space. Before the parafoetal period the paraffin‐coated air space contained 6.4–8.5 per cent O2 and 7.2 per cent CO2. In normal eggs the composition of the gas mixture was 14.2 per cent O2 and 5.6 per cent CO2. During the parafoetal period the air space of paraffin‐coated eggs contained 4.6–6.5 per cent O2 and 7.3–7.7 per cent CO2 as compared with 9.0 per cent O2 and 6.6 per cent CO2 in the controls. Shortly before pipping the O2 content was 5.2 per cent and the CO2 content 9.1 per cent in the paraffin‐coated eggs and 8.6 per cent O2 and 8.1 per cent CO2 in the controls. It has been shown that the time of pipping is accelerated by a decreased O2 content as well as by an increased CO2 content in the air space. The stimulating effect of CO2, however, was about twice that of O2...