In a paper entitled “Acapnia and Shock: Carbon Dioxide as a Factor in the Regulation of Heart Rate,” Henderson describes how he was able to regulate the heart rate of dogs to any rate he desired, from 40 beats or fewer per minute up to 200 or more, by altering their pulmonary ventilation. Henderson noted that even a “slight reduction of carbon dioxide of the arterial blood caused a quickening of the heart rate.”
