The lifetime of a massive star before it begins to deplete its nuclear fuel is less than 5 million years (1). In contrast, the age of the galaxy is more than 10 billion years (2); nevertheless, many massive and short-lived stars have been identified by observations at optical wavelengths. These massive stars must have formed very recently relative to the age of the galaxy, and therefore star formation must be occurring in the galaxy at the present time. ; © 1977 American Association for the Advancement of Science. This work was supported by NASA grants NGR 5-002-281 and NGL 5-002-207 and by NSF grant MPS 74-18555AOI. M.W.W. is an Alfred P. Sloan Foundation Fellow. We thank many colleagues, especially I. Gatley, A. E. Glassgold, J. R. Houck, R. B. Leighton, G. H. Rieke, C. G. Wynn-Williams, and G. Zweig, for their comments on the manuscript.