THE PLACENTA AS AN ENDOCKIN OKGAN 661 



were obtained from the records of 357 infants, born at the Boston Lying-in 

 Hospital, taken on the first, third, fifth, seventh, ninth, eleventh and 

 thirteenth days after delivery, growth data being taken only from the 

 histories of those infants whose sole nourishment was derived from the 

 maternal breast and whose delivery had been normal. Having thus ob- 

 tained a standard based on the methods of weighing, care, and diet in use at 

 that hospital, every patient was given 10 grains of the desiccated placenta 

 three times a day for two weeks, until a sufficient number of observations 

 had been made, the conditions as to diet, weighing, and so forth being the 

 same as obtained with the cases in which no placenta was fed. The data 

 for calculating the growth curves were obtained from 177 infants on the 

 first, third, fifth, seventh, ninth, eleventh and thirteenth days after de- 

 livery. The accompanying chart shows the mean of the percentage change 

 in weight throughout the period of study as regards both sets of infants. 



The results of these experiments demonstrated that the ingestion of 

 desiccated placenta by nursing mothers causes an increase in the rate of 

 growth of 60 per cent of the breast fed infants by the thirteenth day, that 

 the postnatal decline in weight is less in amount, and that the growth 

 capacity per unit weight is enhanced. It is accordingly evident that there 

 is produced in the placenta some substance capable of acting as a stimulus 

 to growth when ingested by the mother and passed on in the lacteal 

 secretion to the infant, and it is not illogical to suppose that the placenta 

 in utero produces a substance acting as a stimulus to fetal growth. This 

 opinion is justified inasmuch as the food value of the milk was not sig- 

 nificantly enhanced and as the total caloric value of the placental material 

 consumed is obviously insufficient of itself to explain the increased weight, 

 even were it all transferred to the milk. 



Conclusions 



The sum total of the evidence now available justifies the inclusion of 

 the placenta among the endocrin organs. It is to be doubted that the 

 placenta produces a specific secretion concerned in the mammary hyper- 

 plasia of pregnancy, and the evidence is cumulatively negative that by 

 any normal secretory process the placenta contributes either to milk 

 secretion or to the etiology of eclampsia. Yet from the data previously 

 recorded and quite recently confirmed by Giesey, that the injection of 

 placental extracts into virgin animals causes a uterine hyperplasia, and 

 from the fact that the rate of growth of breast fed infants is enhanced 

 when they are subsisting upon milk produced during the maternal inges- 

 tion of desiccated placenta, the belief is justified that among the placental 

 functions can be included that of producing a growth-promoting hormone. 



