We may now, in order to clear away what has been to some a stumbling-block—the argument from analogy founded on the case of literary property—notice certain distinctions between the subjects respectively of Patent-right and Copyright. Those things that belong to the province of Patent-right are in their nature capable of being independently discovered or originated, in the same identical form, by a plurality of persons. Of this character are the principles of mechanism, processes of manufacture, and forms or methods accordant thereto. Such, indeed, are, as a rule, actually discovered or invented by several persons, and this very often almost simultaneously. It is otherwise with things that belong to the province of Copyright—literary and artistic combinations, books, pictures, musical compositions, involving any degree of elaboration. Such, at no interval of time, have ever been produced by even one other person except a copyist. This ground for differential treatment is connected with others. In particular, the literary or artistic compositions of any person are perfectly distinguishable from all those of every other. Hence the Copyright privilege is conceded in the absolute certainty that the grantee is their true and only originator, or first producer or creator. No second person can come forward, after the Copyright privilege is secured to an author or artist, and allege that the poem or picture he composed also. To infringe Copyright means to slavishly or meanly copy the work of another. To constitute infringement it is not sufficient that the second person’s book has the same subject and the same purpose in view, and is written in the same spirit as the first; the “matter” must be the same, and in the same form. And so with pictures, the subjects may be the same; the ideas may show great correspondence. _Exactness_ of “matter” and of arrangement is everything. Patent-right, on the contrary, may be infringed where there is no such exactness, and no copying whatever, but complete originality. Disregarding form, it forbids the embodiment and use of _ideas_, even of ideas entirely one’s own. We have thus the inconsistency, or paradox, that the exclusive privileges which have for their province only material objects—which engage only our bodily frame and those senses merely that have their exercise on matter apart from mind (and this is all that patentable inventions do)—carry prohibition into the region of ideas; while those other exclusive privileges, in whose province matter serves only as a vehicle or excitant of things immaterial—conceptions, memories, tastes, emotions—and as an instrument to set the mind a-working and affect the higher senses and faculties—make no such incursions, keeping entirely clear of interference with any man’s practical use of ideas.