Chemical Development in utero

Abstract

In spite of the spectacular advances in scientific medicine which we have witnessed in the last 20 years, there is still a need for information about a number of fundamental, if quite elementary, matters.One of these is the chemical composition of the human body.A knowledge of the quantitative make-up of the bodies of men, women, and children in both health and disease is of value for investiga- tions of the most diverse types, but much of the information available is the result of guess work rather than chemistry.It is proposed to describe the results of an attempt to fill some of the gaps in our knowledge.Von Bezold (1857, 1858) was the first to make an analysis of a human foetus.It weighed 523 g., and he determined both organic and inorganic constituents.During the next 50 years a number of analyses were made, mostly in Germany and France, though one paper from Italy and one from Holland were published.Fehling (1877) studied 21 foetuses varying in weight from 1 to 3,294 g.He was interested only in the amounts of water, nitrogen, and fat, but most workers included inorganic constituents in their analyses (Brubacher, 1891; Giacosa, 1895; Michel, 1899; Hugounenq, 1899, 1900a, b; de Lange, 1900; Camerer, 1900a, b, 1902; Soldner, 1903; Steinitz, 1904; Langstein and Edelstein, 1917).Further data have been provided by Givens and Macy (1933), who analysed 25 foetuses of various ages for water, ash, calcium, and magnesium, and lob and Swanson (1934), who estimated water, fat, nitrogen, sodium, potassium, calcium, magnesium, phosphorus, and chloride in 17 foetuses weighing between 1-7 and 2,915 g. Macy and Hunscher (1934), Coons, Schiefelbusch, Marshall, and Coons (1935) and Garry and Stiven (1936) took all these figures for the chemical composition of the human foetus into consideration in making their calculations of the dietary require- ments of the mother during pregnancy and lactation.Several studies of the chemical composition of the human placenta have been recorded.Full-term placentae have been analysed for water, nitrogen, fat, and ash by Higuchi (1909) and by Pratt, Kaucher, Richards, Williams and Macy (1946).The amino-acids were studied by Koelker and Slemons (1911) and the different fatty constituents by Pratt, Kaucher, Moyer, Richards, and Williams (1946).Masters and Clayton (1940) were particularly interested in the amount of calcium in the placenta at different stages of maturity and Hilgen- berg (1930) in the concentration of iron.These workers confined their studies to the placenta, and no parallel investigation of foetuses and placentae ever appears to have been made.In the present study 19 human foetuses and full- term infants have been analysed for nitrogen, fat.sodium, potassium, calcium, magnesium, phos- phorus, iron, copper, and zinc, and the iodine in a number of thyroid glands was determined.Placentae from 12 of the foetuses were also analysed.Material Thirteen immature foetuses, two of which were twins, six stillborn infants weighing more than 3,000 g., and 12 placentae were obtained through the courtesy of the staff of Addenbrooke's Hospital and the County Maternity Hospital, Mill Road, Cambridge.Details as to foetal ages, sex and weights, and the cause of death are given in Table 1.Age was assessed by measurement of footlength (Streeter, 1920), but this and all other methods are acknowledged to be uncertain, and the chemical findings have therefore all been related to body weight.The livers and spleens were analysed separately from the rest of the body.The thyroid glands of 16 of the foetuses were sent by post to Miss B. W. Simpson, Rowett Research Institute, Aberdeen, for the determination of iodine.The amount of iodine was also determined in the thyroid glands from 16 children between birth and one year, and from 10 older children and three adults.These glands were removed at post-mortem examination at Addenbrooke's Hospital.Preparation for Analysis.The bodies were weighed as soon after delivery as possible, and dissected on an enamel tray so that no blood was lost.The livers and spleens were removed and washed with distilled water, and the washings were added to the main sample.The thyroid glands were dissected out and weighed.The bogdies, together with all the washings, were brought into solution with HCI as described by Venn, McCance, and 205 copyright.