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Spectroscopic studies of the circumstellar (CS) gas around \bp\ since 1984 have led to the detection of strong short-term variations in the CS lines of ionized species (see for instance Ferlet \etal , 1987, A\&A 185, 267, and Lagrange \etal , 1992, A\&A 264, 637 for the visible data and Lagrange \etal , 1988, A\&A 190, 275 for the UV data), tentatively attributed to evaporation from solid, cometary-like bodies falling on the star. Detailed simulations of such a scenario have been developed and reproduce the medium resolution UV as well as the high resolution visible data available so far (Beust \etal , 1990, A\&A 236, 202; 1991, A\&A, 241, 488; Beust and Tagger, 1993, Icarus, in press). In this poster, we will present high resolution UV spectra obtained in December 1992 with the Hubble Space Telescope GHRS. These data (Vidal-Madjar \etal , 1993, A\&A, to be submitted) enable us to confirm the presence of very ionized species around \bp\ such as C\,{\sc iv}, already proposed by Deleuil \etal\ (1993, A\&A 267, 187) from IUE data, but also to detect unambiguously the molecular species CO. The variable parts of other CS lines (e.g., Fe\,{\sc ii}, Mg\,{\sc ii}, Al\,{\sc iii}), observed with unprecedented high resolution and high signal-to-noise, also bring strong support to the evaporating infalling body scenario.
