the scope of the invention as originally claimed. A defective specification could be rendered more definite and certain so as to embrace the Claim made, or the Claim could be so modified as to correspond with the specification; but except under special circumstances, such as occurred in the case of Lockwood v. Morey, 8 Wall. 230, where the inventor was induced to limit his Claim by the mistake of the Commissioner of Patents, this was the extent to which the operation of the original patent could be changed by the re-issue. The object of the law was to enable patentees to remedy accidental mistakes, and the law was perverted when any other end was secured by the re-issue." 11 0. G. 151 (152).

In Stevens v. Pritchard (1876), 4 Clifford, 417, Clifford, J.: (421) "Surrenders are allowed in order that what was imperfect before may be made perfect, and in order that what was before ambiguous may be made clear and certain; and for that purpose the patentee may add whatever was substantially suggested or indicated in the original specifications, drawings, or Patent Office model. New features may not be introduced for the reason that every interpolation of the kind is forbidden by the act of Congress. Errors and defects may, however, be corrected under the conditions specified, and the prohibition that new features shall not be introduced must not be understood as taking away the right to include in the re-issue whatever was substantially suggested or indicated in the surrendered specifications, drawings, or Patent Office model." 10 O. G. 505 (506); 2 Bann. & A. 390 (393).

In Salamander Felting Co. v. Haven (1875), 3 Dillon, 131, Treat, J.: (134) "The repeated decisions by the courts,

The reason of the

and especially by the United States Supreme Court, in the 1st, 17th, and 19th Wallace, indicate with sufficient distinctness, that not only no new matter shall be introduced, but that an enlargement of the original Claim, growing out of the subsequent advance of the art, is not to be tolerated. rule is obvious. Every patent as to novelty or utility depends on the state of the art at the time of the claim made or patent issued, and, therefore, if a party, after learning from a subsequent advance of the art the worthlessness of his original invention, is to be permitted to claim a re-issue incorporating what was not originally in his mind, and what had been afterwards suggested to him only by advances in the art made by others, then he could, it may be, even without any new invention, override all the elements which would serve to test the validity of the new application. In other words, having procured a worthless patent, and having subsequently learned from the advancing art how, by changing the terms of his patent, it could be made of value, he would, if a re-issue, including the new matter, were permitted, have the re-issue not only relate back to the date of the original patent, but absorb within its privileges all subsequent matters, wholly unknown to, and unthought of by him, originally. This rule controls both the Patent Office and the courts. New matter must not be introduced. By new matter is not meant merely the introduction of a new ingredient in a patented composition, but any change in the original specification and Claim whereby a new and substantially different composition and results are secured." 9 0. G. 253 (254).

Further that "new matter" cannot be embraced in a re-issued patent, see

Andrews v. Hovey (1883), 5 McCrary, 181; 16 Fed. Rep. 387; 26 O. G. 1011; Washburn & Moen Mfg. Co. v. Haish (1880), 10 Bissell, 65; 19 O. G. 173; 4 Fed. Rep. 900; Giant Powder Co. v. California Powder Works (1875), 3 Sawyer, 448; 2 Bann. & A. 131; Glue Co. v. Upton (1874), 1 Bann. & A. 497; 4 Clifford, 237; 6 O. G. 837; Carew v. Boston Elastic Fabric Co. (1871), 3 Clifford, 356; 5 Fisher, 90; 1 O. G. 91.

That a re-issue blending old matter and new matter in the same Claim is void, see Cahart v. Austin (1865), 2 Fisher, 543; 2 Clifford, 528.

That enlarged Claims are to be carefully scrutinized to see that they contain no new matter, see Tyler v. Welch (1880), 17 O. G. 1508; 3 Fed. Rep. 636; 18 Blatch. 209.

That new matter cannot be inserted in the re-issue though invented by the patentee and inadvertently omitted by him from the original, see Atwater Mfg. Co. v. Beecher Mfg. Co. (1881), 8 Fed. Rep. 608.

That where the original patent had no model or drawing, no new matter can be inserted in the re-issue on the ground that the inventor had it in his mind when the original application was filed, see Ex parte Dieckerhoff (1877), 12 O. G. 429.

That where the same idea is found in the original specification and drawings, there is no new matter, see Christman v. Rumsey (1879), 58 How. Pr. 114; 17 Blatch. 148; 17 O. G. 903; 4 Bann. & A. 506.

That " new matter" in a re-issue is such an enlargement or alteration in the original specification and Claims as to include combinations or results which did not necessarily flow from the inven tion as originally described, see Putnam v. Yerrington (1876), 2 Bann. & A. 237 ; 9 0. G. 689.,

That "new matter" in a re-issue is such as changes the invention or introduces what might be the subject of a new patent, see Seibert Cylinder Oil Cup Co. v. Harper Steam Lubricator Co. (1880), 4 Fed. Rep. 328; Powder Co. v. Powder Works (1878) 98 U. S. 126; 15 O. G. 289.

That nothing can be regarded as "new matter" unless it affects the substance of the invention, see Christman v. Rumsey (1879), 17 O. G. 903; 4 Banu. & A. 506; 58 How. Pr. 114; 17 Blatch. 148; Ex parte Carlock (1875), 8 O. G. 191.

That where the re-issue seeks to cover an infringing device it will be closely scrutinized, but will be valid if clearly for the same invention as the original patent, see Crompton v. Knowles (1881), 7 Fed. Rep. 199.

That unless it clearly appears that the re-issue contains new matters, substantially different from the original, it will be held valid, see Thomas v. Shoe Machinery Mfg. Co. (1878), 16 O. G. 541; 3 Bann. & A. 557.

That where the Claim in the re-issue states what the original Claim must have been construed to mean, there is no new matter, see Gold & Stock Telegraph Co. v. Commercial Telegram Co.

§ 669. Although no formal statement of this rule may be found in the reported cases, it has nevertheless been too often acted on by the courts to be disputed. The decisions cited in the subsequent paragraphs show that the test applied is not that of the presence of the subordinate or dependent inventions in the Claims of the original patent, but their capability of being claimed therein under the rules of joinder. It is taken for granted, where there are no indications to the contrary, that the patentee intended to secure by his original patent all those dependent and auxiliary inventions which he then described as resulting from his inventive act, and in the absence of any abandonment or estoppel, he is permitted to insert in his re-issue any such inventions which could lawfully have been claimed in the original. The few cases which depart from this rule are so manifestly unjust in their effect, and involve so wide a divergence from the settled principles of Patent Law, that they cannot be regarded as authority against the current practice of the Patent Office and the general position of the courts.

Within the limits of the doctrine thus declared there are, however, certain variations which deserve attention. Inventions capable of joinder may be either (1) mutually separable, or (2) mutually inseparable, or (3) one may be unable to subsist without the other though the

other, on the contrary, could independ ently exist. Where the inventions are mutually inseparable a patent for one impliedly covers the other and is a bar to any subsequent patent therefor. The same is true where an invention, with which another is inseparably connected, has been patented. As in both these cases the unclaimed invention must either have been within the intended scope of the original patent, or have been abandoned to the public under circumstances which prevented the public from enjoying it by reason of its connection with the matter expressly patented, it is always a fair presumption that the patentee, by describing it in his original specification, endeavored to bring it within his monopoly and consequently has a right to claim it in his re-issue. But where the inventions are mutually separable or the invention sought to be introduced into the re-issue is not inseparable from the one claimed in the original patent, no such presumption can arise. Here it was optional for the inventor to have embraced the inventions in the same or different patents, and from the fact that he describes them in connection with the invention claimed in the original, no inference can be drawn that he did not intend to abandon them to the public or to procure for them a separate patent. In these cases the validity of the Claims by which they are appropriated in the re-issue must de