INTRODUCTION. 



In our observations on the gaseous metabolism of infants, which were 

 begun over three years ago, we have been impressed by the fact that 

 while observations on three or four infants would admit of conjectures 

 which might subsequently be in part verified by multiplication of data, 

 yet of themselves they could necessarily have very little conclusive 

 value. Accordingly, as it is the purpose of this laboratory to secure 

 sufficient data to eliminate, so far as possible, the personal equation, 

 we frankly stated in our earlier publication 1 that we were still occupied 

 in "overcoming the paucity of results obtained with normal infants," 

 and similar statements were made with regard to the new-born infants. 

 Our observations of new-born infants were begun in the latter part of 

 1913 and were freely discussed with the investigators working in the 

 same field. There seems to have been a disposition on the part of some 

 investigators to relieve us of the responsibility of interpreting certain of 

 our results; consequently, we present here our complete data in regard 

 to the character and amount of the metabolism of 105 new-born infants, 

 74 of which were studied within 24 hours of birth. 



EMBRYONIC CONDITIONS. 



Although the interest of the embryologist in the prenatal develop- 

 ment of the infant begins at the moment of conception, it is not until 

 the fetus has reached a considerably advanced stage of development 

 that an intelligent interest can be taken in its metabolism. Histological 

 studies show that the composition of the embryo is not materially dif- 

 ferent from that of the adult organism. Food is carried to the placenta 

 by the blood of the mother and we have no reason to believe that there 

 is in the prenatal life any marked difference between the mother and 

 the fetus in the character of the katabolism. On the other hand, 

 histological studies 2 do show that there is in the embryo a relatively 

 large proportion of glycogen. While this is shown microscopically, 

 it has not as yet received verification by chemical analysis. At the 

 present time, therefore, the common belief in a large supply of glycogen 

 in the embryo is based solely upon histological studies, made almost 

 entirely on animals, and it is well known that the results of histological 



Benedict and Talbot, Am. Journ. Diseases of Children, 1914, 8, p. 43. 



2 Gierke, Lubarsch-Ostertag's Ergeb. Jahrb., 1907, 11 (2), p. 880. Also, Lubarsch, Virchow's 

 Archiv, 1906, 183, p. 188. Most of the work has been done on animals, with the single exception 

 of that by Lubarsch. Lubarsch examined a 9-weeks human embryo and a 4 to 5 months human 

 fetus, and concluded that the amount of glycogen varied with the age and the species. The 

 muscles contain a considerable amount of glycogen even in the embryo, while glycogen is 

 only deposited in the liver in later embryonic life. Mendel and Leavenworth (Am. Journ. Physiol. , 

 1907-8, 20, p. 117) add to Gierke's extended review of the literature on the subject. 



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