nOWEtiL V. LINDSAY. 295 �of the combination are old. Upon the highest authority, it therefore conelusively appears, I think, that complainants are not in a position to claim that their slotted beam was of itself a new invention or discovery. And, as before stated, it is not enough to say that it was not before used for hold- ing cultivator teeth ; for it cannot be reasonably claimed that the mere application of an old thing to a new use in a com- bination is such invention of a new part as would bring the case within that class of combinations where the appropria- tion of a single part is an infringement. But it is contended that the slotted beam ia the distinctive and essential fea- ture of complainants' invention, and should be regarded as such in passing on the question of infringement. The court must, however, look at the entire specifications and claim of the patentees, in determining what their invention is. The combination is an entirety. Unless it is maintained as such the whole of the invention fails. If one of the elements is given up the thing claimed disappears. Where a patentee, suing for an infringement, declares upon a combination of elements which he asserts constitutes the novelty of his invention, he cannot abandon a part of such combination and maintain his claims to the rest. Much less can he prove any part of his combination immaterial or useless. Vance v. CampbeU, 1 Black, 427. The different parts may perform more or less important functions, but each and ail are essen- tial to make the thing which the patentee bas claimed as his invention. �It follows, from what bas been stated, that the defendants do not infringe the complainants' patent by merely using the slotted beam. They do not infringe unless they have appro- priated the entire combination. The patentees declare in their specifications what their invention is. They expressly say, inter alla, that it consists "in applying to the shank of the tooth a eurved brace-bar, the upper end of which passes through a slot or mortise in the beam." The defendants use the slotted beam, the shank of the tooth, and the clamping boit. But in their device there is no brace-bar welded to the shank, and passing up through the mortise in the beam. ��� �
