When analyzing the spectral energy distributions of early type stars as measured at Cerro Calán, we find that many of them have a feature which we have called ΔD (Gutiérrez-Moreno et al., 1968); the internal error of the measure of ΔD for a single star is ±0.02. An analysis of the spectrum scans and the energy distributions shows that this feature may be interpreted as an emission in the Balmer continuum. A few stars have values of ΔD<0, and a comparison of their scans with those of normal stars (ΔD=0) suggests an absorption larger than normal in the Balmer continuum.