T 0226/85 (Stable bleaches) of 17.03.1987

Even though a reasonable amount of trial and error is permissible when it comes to the sufficiency of disclosure, e.g. in an unexplored field or, - as it is in this case - , where there are many technical difficulties, there must then be available adequate instructions in the specification or on the basis of common general knowledge which would lead the skilled person necessarily and directly towards the success through the evaluation of initial failures or through an acceptable statistical expectation rate in case of random experiments (following decision T 14/83, "Vinylchloride resins", OJ EPO 1984,105).