(after stating the facts as above). The Carmichael patent relates solely to the treatment of natural teeth. The process consists'in the preparation of the tooth by the cutting of grooves on the sides thereof, and also on the end away from the gums; the application of a gold leaf to the tooth thus prepared, to obtain its configuration, thereby obtaining a base; the removing of this base from the tooth; the building up of this base to make it firm; andv finally the fitting of this base, thus built up, to the tooth by means of cement.

All this was done in the Williams patent, but in connection with teeth;put into bridge work only; so that whatever novelty there is in the Carmichael patent is to be found in the transferring of this process from bridge work teeth to natural teeth — from work upon teeth on the dentist’s work bench to work upon teeth in the mouth.

The' object of the base thus built up, in bridge work, is to give foundation to the tooth — something to take the place of the gum and the root in giving fastening to the artificial tooth; the object in the application of the base thus built up in connection with live teeth is ter give an artificial enamel or covering to the tooth, and therefore simply hangs upon the top of the tooth — has nothing of the function of a,foundation. But does this change the identity of the actual thing done?. Is this difference of function a difference of .process? We think not. The material out of which the base is made, the mechanical means by which it is made, and the process are the same in both cases. That being the case, the function of the artificial foundation to the natural tooth, though different from the function of the same thing upon the bridge-tooth, does not change the one- thing into another thing when that one thing is identical with the other thing in every way except mere function.

*939Whatever merit the Carmichael patent has is in the possibility that Carmichael was the first to discern that the grooving o£ a live tooth could take place without injuring it; and because of that was the first to apply this old mechanism to-a live tooth. We do not say that such is the fact — we are only assuming it as a possibility. For even in that case the most that can be said of what Carmichael did is that it was a discovery in dentistry. The mechanism that Carmichael used to carry out his discovery — the utilization of the Williams mechanism— is none the less old; and it is with the mechanism that this patent deals.

The decree of the Circuit Court is affirmed.