not attempt at the time to identify the nature of this stimulatory
substance, but since it was derived from living organisms, he called it
"Bios." Soon after the discovery of vitamines the bacteriologists began to
discover that they or an analogous factor apparently played a part in the
growth of certain strains of bacteria, especially the meningococcus. In
1919 Roger Williams working in Chicago University was struck with the
bearing of Wildier's work on the vitamine hypothesis and formed the theory
that Wildier's "bios" might be the water-soluble vitamine "B." He
proceeded to test out this theory and demonstrated that extracts of
substances rich in the "B" vitamine had a marked effect on the stimulation
of yeast growth. He developed these experiments and devised a method of
comparing the growth of yeast cells when stimulated by such extracts. The
results were so striking as to appear to justify his view and he then
suggested that his method might be used as a test for the measure of "B"
vitamine in a given source. William's method consisted essentially in
adding the extract of an unknown substance to hanging drops in which were
suspended single yeast cells and observing the rate of growth under the
microscope. Soon after, Miss Freda Bachman reinvestigated the problem with
various types of yeast and found that practically all types of yeast
respond to the stimulation of these "bios" extracts. Her method consisted
in the use of fermentation tubes and the stimulatory effect was measured
by the amount of CO_2 produced in a given time. By this method she
confirmed Williams' view that the "bios" of Wildier was apparently
identical with vitamine "B" and that most yeasts require this vitamine for
their growth. She also suggested that her method might be made the basis
of a test for vitamine content. In 1919 Eddy and Stevenson made extended
experiments with these two methods in the attempt to improve the technique
and make it serve as a quantitative measure. Their experiments served two
purposes, first to bring out certain difficulties in the methods of the
two authors from the quantitative viewpoint and the development of a