ABSTRACT
It is now generally accepted that living systems appeared on the earth after a long chemical evolution. Astrophysical data have indicated that sulfur took part in stellar evolution and can be detected in the interstellar medium in simple combination with other elements (H2S, CS, NS, SO, SO2, SiS, HNCS, CH2S, CH3SH) (Herbst and Klemperer 1976, Winnewisser and Herbst 1987). The spectral lines of our sun show no indication of sulfur whereas those from some of the hotter stars and
nebulae strongly suggest its presence (Bowen 1929, Lockyer 1907). Free sulfur (1.24% by weight) was found during the chemical analysis of a meteorite which landed near Alais, France in 1806 and to a lesser extent in other heavenly bodies that have fallen to earth, although usually in combination with iron as pyrites (Roscoe 1863). From such information and the geological evidence that large quantities of sulfur are now present upon earth, it is reasonable to assume that sulfur was included early in the primitive medium during the formation of the earth but probably only as the reduced form of sulfides, notably hydrogen sulfide (Holland 1962, 1974).
