56 The Philippine Journal of Science i9i6 



during the passage of vomitus through it as some authors are 

 inclined to believe.* 



The similarity of the curves, Plate I, fig. 1, and Plate II, 

 fig. 2, affords strong evidence that the glottis closes in the act 

 of vomiting.'^ We have observed, also, when the trachea is 

 connected with a mercury manometer and the dog is allowed to 

 respire through a side tube the terminal opening of which has 

 the combined area of the two nostrils of the animal, that vomit- 

 ing does not cause a rise of intrapulmonic pressure. The in- 

 creased pressure noted when the trachea is not occluded, then, 

 must be associated with partial or complete closure of the glottis. 

 On the ingenious suggestion of Prof. R. B. Gibson, of the 

 College of Medicine and Surgery of this University, the condition 

 of the glottis during emesis was further studies as follows: A 

 tracheal cannula was inserted into the trachea — opening directed 

 toward the glottis — and by a Y-tube was connected with a mer- 

 cury manometer and water-air-pressure pump as shown in fig. 1. 

 If the water is turned on, a current of air flows from the pump 

 through the Y-tube, tracheal cannula, and out of the glottis 

 during quiet respiration, without raising the mercury in the 

 manometer, but if the lumen of the rubber tube connecting the 

 tracheal cannula with the Y-tube be occluded, the current of 

 air is deflected toward the manometer and the mercury rises, 

 falling partially after about four seconds, and then oscillates 

 about this new level till the occlusion is removed. An illustra- 

 tion of this is Plate II, fig. 1. Plate I, fig. 2, shows the curves 

 obtained when the dog vomited. The rise of pressure indicates 

 an obstruction to the passage of air through the naso-laryngo- 

 tracheal passages, and as under the condition of the experiment 

 the dog can accomplish this only by closing the glottis, it serves, 

 therefore, as evidence that this organ closes in the act of vomiting. 



The closure of the glottis may persist for ten seconds. Its trac- 

 ing, when taken simultaneously with that of the intrapulmonic 

 pressure, shows that the glottis stays closed until about the end 

 of vomiting. Whether the glottis opens before or after the in- 

 creased intrapulmonic pressure has returned to normal, we have 

 not satisfactorily ascertained. The tracings which we could only 

 take on slowly moving drums are not conclusive. However, our 

 objective observation on the movement of air in the trachea 



* See Howell, Text-book of Physiology. 6th ed., W. B. Saunders Co., 

 Philadelphia & London (1915), 736. 



' "Act of vomiting" is used here and in the following pages to designate 

 the series of events beginning with the first deep inspiration to the ap- 

 pearance of vomitus in the mouth. 



