452 REPRODUCTION AND DEVELOPMENT 



Respiration during childhood differs likewise from the adult process 

 chiefly in its greater activity and in its larger variability under different 

 circumstances. The breath-movements are more diaphragmatic and 

 abdominal than in the adult, the intercostal muscles being relatively 

 weak. The respiratory movements of the chest, according to Uffelmann, 

 are at birth 35 per minute; at one year old, 27; at two years, 25; at six 

 years, 22, and at twelve years, 20. Very often, indeed, however, one sees 

 breath-rates averaging five higher than these figures indicate. The 

 breath-rhythm is very vague during the first years of life, and varies 

 greatly from little causes, such, for example, as emotions, muscular 

 activity, and physiological variations in body-temperature. Periods of 

 apnea of short duration are normal, while the rate on either side of such 

 a period may vary many breaths per minute, being at one time 70 and at 

 another 40. The imperfect connection of the various vital centers in 

 the medulla plus the relative strength of the emotional expressions will 

 in part explain these irregularities. 



The bronchi and trachea are proportionally larger than in adulthood, 

 while the alveoli are relatively smaller. Partly because of this we find 

 the common pneumonia of infancy to be of the bronchial type, while 

 that of middle life affects the alveoli more especially: lobar pneumonil, 



Body-temperature is another function of the child-organism which is 

 characteristically variable and irregular by the adult standards. For a 

 few days after birth, owing to the lessening in the metabolism from lack 

 of assimilation, the degree of heat may fall a degree or so below the daily 

 average of about 37.2 (99 F). Exposure decreases the temperature 

 readily. Raudnitz found that a cold bath raised the temperature (as 

 indicated in the rectum) in vigorous new-born children, but lowered it 

 in feeble infants. If we take 37.2 (99 F.) as the average temperature 

 of the first ten years, it must be considered the same as all averages 

 that is, as more or less artificial. The causes of variation in temperature 

 are numerous, and many of these in childhood frequently produce 

 effects much more marked than they would among adults. Thus, 

 excitement, especially mental excitement, and intestinal irritation of a 

 trivial degree, weak toxins, or fatigue may raise the temperature of the 

 child of two or three years in a way not observed in the child of ten nor 

 in later life. This great variability is especially marked in girls, but in 

 both girls and boys it constitutes the chief peculiarity of the temperature 

 during childhood. A temperature of 39 (102.2 F.) in an adult 

 usually means something of consequence, but in a three-year-old it often 

 signifies nothing which a movement of the bowels will not promptly 

 dispel. Here, as elsewhere, we see the signs of neural incompleteness 

 and of nervous instability. 



The senses of children are in general more acute than are those of 

 adults, save in so far as training is involved in developing the actual 

 sense-organs. Sensations, however, by themselves are of little use 

 comparatively, .aside from their meanings to the individual. The child 

 is relatively deficient in his apperceptive power and does not yet know, 



