POSTNATAL GROWTH OF HEART, KIDNEYS, LIVER, AND SPLEEN. 267 



average as they are below it in tuberculosis. It may be equally inaccurate to 

 choose only individuals who have died suddenly, because in shock the splanchnic 

 vessels are dilated and the organs may weigh more after death than during life. 

 It may be difficult to devise a method of determining the weight of the organs 

 during life, although Bardeen (1918) has recently succeeded in obtaining what 

 seems to be a satisfactory method of determining the heart weight in the living 

 subject. Any results so far obtained from weighing the organs of the dead are 

 necessarily inadequate and deductions from them should be utilized with caution. 

 It seems best to take all cases, regardless of the cause of death, and study them 

 with as full knowledge as possible concerning their antecedents. 



The data for the present study consist of records from the pathological 

 department of the Charity Hopital, New Orleans, and from the pathological 

 department of the Johns Hopkins Hospital, Baltimore. Some of those from the 

 Charity Hospital were copied by Dr. Wilmer Baker, and all of them represent 

 the submerged tenth of the semi-tropics; whereas those from the Johns Hopkins 

 Hospital represent an average hospital population of a large, modern city. No 

 attempt has been made to select only normal organs, but where an organ is ob- 

 viously diseased, so as to materially affect its weight, it is discarded. 



HEART. 



The weights of the organs were treated as Mall (1918) treated the crown- 

 rump length of embryos; i. e., each individual is represented on a chart one meter 

 square, with the weight as the ordinate and the age as the abscissa. The growth 

 of the heart in both sexes and both races (white and negro) appears to be divided 

 into three periods of rapid growth, alternating with three periods of slow growth; 

 the first period of rapid growth is between 3 and 9 months, the second from 2 to 8 

 years, and the third from 14 years to maturity. There is no relative decrease in 

 the increment of growth in each consecutive period from the first to the third. 

 The rate of growth during any period is based upon the size of the heart at the 

 beginning of that period of growth. 



The heart of the female is smaller than that of the male except at about the 

 tenth year, when it is larger. This corresponds to the time at which the stature 

 of the female is greater than that of the male. Heart weight, size of individual, 

 and physical activity are synchronous. For the first few months after birth the 

 child is not very active, and during this period the growth of the heart is slow. 

 From 6 to 9 months of age the child becomes more active, the growth in stature 

 increases, and the heart enlarges rapidly. Then follows a less active period, 

 when the child is learning to stand and walk, and during this time the heart is 

 proportionately inactive. After the child has learned to walk and run, a period 

 of great activity ensues and the stature and heart weight increase rapidly up to 

 the age of 8 years. After this there is a slowing down of this increase, followed by 

 an acceleration, in girls at about the age of 10 years, in boys somewhat later; at 

 this age, therefore, girls surpass the boys in stature and heart weight, to be again 



