Normal infantile respiration in sleep is quiet, noiseless, save for the soft low inspiratory murmur, always nasal, chiefly diaphragmatic. During the first month its rhythm is irregular, there are frequent pauses and at times it is deeper, as in the Cheyne-Stokes variety. Its rate varies from 30 to 45. At the end of the third year it is regular and has a rate of 24. The rhythm is changed by very slight impressions. The movements seen are the ample ones of the abdomen, the lesser ones of the thorax and those of the nasal alæ. There is no drawing in of the fleshy portions of the thorax, the mouth is closed and the act of nursing can be completed without interruption.
Widely differing in its symptoms from that due to pulmonary or bronchial affections, abnormal respiration from obstructions in the upper air tracts is more difficult to trace to its