volumes), after which time no further rotation is imparted to the micrometer head even though the motor may continue to run. If required, a second 0.5ml. application may be made-i.e., 1.0 ml. in all. By the ninhydrin method of Yemm and Cocking (51, known concentrations of either a single amino acid or mixtures thereof applied as “0.5-ml. Spots” to chromatography paper and run in vario m solvents were recovered with the same degree of accuracy as for a single
O.OOj-ni1. application of similar soluLions 100 times more concentrated.
tional Institutes of Health, Public Health Service.
ACKNOWLEDGMENT
Thanks are due t o lvilliam Goebel and Joseph Poppel, both of this institution, for the machine work and photography, respectively. The work described jyas performed in the course of an investigation supported (in part) by a research grant (H-1917) from the Sational Heart Institute, of the Ka-
LITERATURE CITED
(1) Glazko, A. J., McGinty, D. -4., l l l l l t V.A., Wilson, M. L., Ward, C. S., J . B i d . Chem. 179,109 (1949 ). (2) 1loore, A. hi,, ~ ~J . B., science ~ l 118, 19 (1953). (3) I-rbach, I
