SOME NOTES ON THE FORM OF THE CURVE OF 



CARBON-DIOXIDE EXCRETION RESULTING 



FROM MUSCULAR WORK FOLLOWING 



FORCED BREATHING^ 



G. O. HIGLEY 

 (Ohio Wesleyan University, Delaware, Ohio) 



(WITH PLATE 4) 



In an earlier research^ an attempt was made to determine how 

 soon after the beginning of work an increase in the production of 

 carbon dioxide begins to show itself in the expired air. This time 

 (the latent period) was at first found to vary from three to fourteen 

 seconds. Now, clearly, such periods are not long enough to cor- 

 respond with the time required for the carbon dioxide formed in the 

 muscles at the first muscular contraction to reach the outside air. 

 It must first diffuse into the blood from the tissues where it is 

 formed, then traverse the venous half of the systemic circulation, 

 the right side of the heart, and the arterial half of the pulmonary 

 circulation, and finally diffuse into the air of the alveoli before any 

 of it can appear in the breath. From the conclusions of Stewart 

 and others it appeared that from fifteen to twenty seconds is the 

 least possible time required for the blood to traverse this distance, 

 to say nothing of the diffusion time. It was finally found that 

 the sudden increase in the rate of excretion of carbon dioxide, after 

 the beginning of work, was due primarily to a better Ventilation of 

 the lungs, while the continuation of the increase was due to the 

 Ventilation of the blood and tissues as well. A recognition of this 

 fact led to the following modification of the method for the de- 

 termination of the latent period of carbon dioxide excretion : 



^ This paper was accepted for publication by the officers of Section VIII, 

 d. Eighth International Congress of Applied Chemistry, and was read before 

 the Section at a stated meeting on September 11, 1912; Biochemical Bulletin, 

 1912, ii, p. 153. 



^Higley and Bowen: American Journal of Physiology, 1904, xii, p. 311. 



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