A patentee who took the important but long delayed and therefore not obvious step from the pulling of candy by hand to the performance of the same function by machine, the ultimate effect of which, with the mechanical and patentable improvements of his device, was greatly to reduce its cost, and to enlarge the field of the art, was a pioneer. The machine patented may be imperfect in operation, but if it embodies the generic principle, and works - that is, if it actually and mechanically performs, though only in a crude way, the important function by which it makes the substantial change claimed for it in the art, it is enough. It is not necessary, in order to sustain a generic patent, to show that the device is a commercial success. The presumption of priority and novelty which arises from the granting of a patent has greatly increased weight when the claim of the inventor was subjected to close and careful scrutiny in the Patent Office under the stimulus of a heated contest.