Sodium and ammonium sulphates form similar compounds with nickelous sulphate.
From nickelous carbonate and hydrochloric acid, as the acetate.
By crystallising a mixture of nickelous and potassium sulphates.
By neutralising acetic acid with nickelous carbonate, and gently concentrating by evaporation, so that crystals may form.
In other respects, its physiological action seems to be very similar to that of nickelous oxide.