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 investigations 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 (