THE RESPIRATORY RATIO: A PRELIMINARY NOTE

The respiratory ratio which I wish to describe is obtained as follows: The patient is told to take a deep breath and to hold it as long as he can. He is further instructed to raise his hand when he feels that he must expire. Some little time (five minutes) is then spent in the ordinary examination; then the patient is told to expire fully and not to breathe in till he is compelled to do so, when he again must raise his hand. The time from the beginning of either of these phases of respiration to the time of raising the hand is noted and the ratio thus obtained. The period during which the breath has been held in full inspiration by healthy individuals has varied from 40 to 70 seconds. The period during which the breath has been held in full expiration in the same individuals has varied