1. The invention for which reissued letters patent No. 1904,
dated March 21, 1886, were granted to the Goodyear Dental Vulcanite
Company was a set of artificial teeth, as a new article of
manufacture consisting of a plate of hard rubber with teeth, or
teeth and gums, secured thereto in the manner described in the
specification by embedding the teeth and pins in a vulcanizable
compound so that it shall surround them while it is in a soft
state, before it is vulcanized, and so that when it has been
vulcanized, the teeth are firmly and inseparably secured in the
vulcanite, and a tight joint is effected between them, the whole
constituting but one piece.
Held that the invention being
a product or manufacture made in a defined manner, and not the
product alone, separated from the process by which it is created,
the process is as much a part of the invention as is the material
of which the plate or product is composed.
2. Those letters are not infringed otherwise than by using the
material and the process or their equivalents. A plate made of
celluloid is not, therefore, an infringement, as celluloid is not
an equivalent for hard rubber, and in preparing it for that purpose
the process, which is inseparable from the invention, cannot be
employed.
This was a bill in equity brought by the Goodyear Dental
Vulcanite Company against Charles G. Davis, alleging his
infringement of reissued letters patent No. 1904, dated March 21,
1865, and granted to the complainant, as assignee of John A.
Cummings, for an improvement in artificial gums and plates.
The bill was, on a final hearing upon the pleadings and proofs,
dismissed. The complainant appealed here.
The facts are fully stated in the opinion of the Court.
Page 102 U. S. 223
Mr. JUSTICE STRONG delivered the opinion of the Court.
The invention described in the Cummings reissue patent is
claimed in the words following: "The plate of hard rubber or
vulcanite, or its equivalent, for holding artificial teeth, or
teeth and gums, substantially as described." The claim cannot be
understood without reference to the details given in the
specification. In that it is said to consist
"in forming the plate to which the teeth, or teeth and gums, are
attached, of hard rubber, or 'vulcanite,' so called -- an elastic
material possessing and retaining in use sufficient rigidity for
the purpose of mastication, and at the same time being pliable
enough to yield a little to the motions of the mouth."
The mode of "forming" the plate is then minutely described. The
earlier steps of the process need not be particularly noticed. They
relate to the formation of a plaster mold, fitted to the
corresponding part of the mouth, with the artificial teeth adhering
in the mold in exactly the relative position they are to occupy in
the hard rubber plate. The specification then proceeds as
follows:
"The teeth are provided with pins projecting therefrom in such a
manner that the rubber which is to constitute the plate will close
around them, and by means of them hold or secure the teeth
permanently in position. The plaster mold, with the teeth adhering
therein, as just described, is now filled with soft rubber, a
little at a time, pressed in with the finger or in any other
convenient way, and care is to be taken that the rubber is made to
completely fit into the cavities and around the protuberances,
including the pins, and is filled in to the thickness or depth
desired to form the plate."
"I then" (says the patentee)
"lock the rubber plate in position by shutting the other half of
the plaster mold over it, to insure its retaining its exact form
while warming, and then heat or bake it in an oven or in any other
suitable way. The soft rubber or gum so inserted into the mold is
to be compounded with sulphur, rubber, &c., in the manner
prescribed in the patent of Nelson Goodyear, dated May 6, A.D.
1851, for making hard rubber, and is to be subjected to sufficient
heat to vulcanize or harden it, substantially as directed in that
patent. It is also to be colored in imitation of the natural gums
by mixing it with vermillion or other suitable coloring matter
while in the soft
Page 102 U. S. 224
state. After the plate Has been heated sufficiently to harden it
or convert it into hard rubber or 'vulcanite,' so-called, the mold
is removed and the plate is polished ready for use."
Such is the description both of the material of which the plate
is formed and of the method or process by which it is made.
We had occasion in
Smith v. Goodyear Dental Vulcanite
Company et al., 93 U. S. 486, to
construe this patent and determine what the invention claimed and
patented really was. We held it to be
"a set of artificial teeth, as a new article of manufacture,
consisting of a plate of hard rubber with teeth, or teeth and gums
secured thereto in the manner described in the specification, by
embedding the teeth and pins in a vulcanizable compound, so that it
shall surround them, while it is in a soft state, before it is
vulcanized, and so that when it has been vulcanized, the teeth are
firmly and inseparably secured in the vulcanite, and a tight joint
is effected between them, the whole constituting but one
piece."
We said, "The invention is a product or manufacture made in a
defined manner. It is not a product alone, separated from the
process by which it is created." The process detailed in the
description antecedent to the claim and referred to thereby is as
much a part of the invention as are the materials of which the
plate or product is composed. Both are necessary elements of it.
Hence, to constitute an infringement of the patent, both the
material of which the dental plate is made, or its equivalent, and
the process of constructing the plate, or a process equivalent
thereto, must be employed. It is therefore essential to a correct
determination of this case to consider what was the material made
by the patentee an element of his invention and what can be
considered an equivalent therefor.
It is impossible to read the specification of the original
patent, or that of the reissue, upon which this suit is founded,
without the conviction that the patentee had in mind primarily a
single substance for his material, and that one of a peculiar
character, itself a compound discovered and patented not long
before. Thus, in the original, which was loosely drawn, the
invention was said to consist
"in forming the plate and gums, to which the teeth are attached,
of rubber, or some other elastic material,
Page 102 U. S. 225
so indurated as to be rigid enough for the purpose of
mastication and pliable enough to yield a little to the motions of
the mouth, and in one piece, the teeth being embedded in the
elastic material while the said material is in a soft condition,
and then baked, with the gums and plate, so that the teeth, gums,
and plate will all be connected, forming, as it were, one
piece."
And again,
"the plate and gums are formed of one piece, and of rubber, or
of rubber and the compounds commonly employed therewith, or of
gutta-percha, or, in fact, of any elastic substance which can be
reduced to a soft condition and then vulcanized or hardened
sufficiently to answer the purpose. The rubber or other material
used is first molded to fit the shape of the mouth, and the gums
formed, and while soft and pliable the teeth are embedded in the
gums. . . . The teeth, gums, and plate, being thus connected, are
then baked until the elastic material becomes sufficiently
vulcanized, when the process is completed."
The claim also expressed the same thought. It was
"forming the plate and gums in which the teeth are inserted, in
one piece, of hard rubber or vulcanite,
i.e., an elastic
material which can be hardened sufficiently for mastication, and
retain a portion of its elasticity, so as to yield a little to the
motion of the mouth, as herein set forth, and for the purposes
specified."
Though the specification spoke of rubber, or of rubber and its
compounds commonly employed therewith, or of gutta-percha, or of
any elastic substance that can be reduced to a soft condition and
then vulcanized, or hardened sufficiently to answer the purpose, it
is evident that only such substances were intended as are either
soft in their natural condition, and capable of vulcanization, or
if hard naturally, and reduced to a soft state, were then capable
of being vulcanized or hardened by baking. The description implies
an exclusion of all substances which have not such capabilities. If
not, then gold plates would have been within the patent, if the
material only be considered, for gold is elastic when in thin
plates. It is capable of being reduced to a soft condition, and it
hardens by cooling; but it does not harden by heat or baking, nor
is it capable of vulcanization.
If, now, we turn to the specification and claim of the reissued
patent (which, of course, cannot be more comprehensive
Page 102 U. S. 226
than the original), it will be found that the material is still
more distinctly and exclusively pointed out. The material is, so
far as possible, restricted to a substance either vulcanized or
capable of vulcanization. There the invention is said to consist
"in forming the plate to which the teeth, or teeth and gums, are
attached, of hard rubber or vulcanite, so called, an elastic
material," of certain capabilities mentioned. Not an intimation is
given that any other substance than hard rubber, or its synonym,
vulcanite, would meet the requirements of the invention. Throughout
the specification the patentee speaks again and again of his
invention as a hard-rubber plate, and he describes minutely the
process or mode of making it. After having mentioned the
arrangement of the teeth in a mold, he says:
"The plaster mold, with the teeth adhering therein, is now
filled with soft rubber, a little at a time, pressed in with the
finger, or in any other convenient way,"
&c.
"I then lock the rubber plate in position by shutting the other
half of the plaster mold over it to insure its retaining its exact
form while warming, and then heat or bake it in an oven, or in any
other suitable way. The soft rubber, or gum so inserted in the mold
is to be compounded with sulphur, rubber, &c., in the manner
prescribed in the patent of Nelson Goodyear, dated May 6, A.D.
1851, for making hard rubber, and is to be subjected to sufficient
heat to vulcanize or harden it, substantially as directed in that
patent."
Thus it appears that whatever the material used in the
construction, a dental plate, according to the patent, was required
to undergo a process of vulcanization in the manufacture, and to be
made what it is, whether denominated rubber, hard rubber,
vulcanite, or other elastic material, by that process. Every
substance not capable of vulcanization by that process was
therefore necessarily excluded from the reach of the patentee's
invention. Nothing could more plainly show that a dental plate made
of any other material than a compound, vulcanized according to
Nelson Goodyear's process, was not intended by the patentee and by
the Patent Office to be covered by the patent. By Goodyear's
patent, caoutchouc, or soft rubber, is converted into hard rubber
-- that is, vulcanized, by mixing sulphur with it in about the
proportions of from four ounces to a half pound of the
Page 102 U. S. 227
former to a pound of the rubber, and then heating the compound
during a period of from three to six hours, to the temperature of
from two hundred and sixty to two hundred and seventy-five degrees
of Fahrenheit. The use of that process was made indispensable to
the invention, and its product was the material of which the
patented plate is constructed. If, when the patent was granted,
there were known substances, other than rubber or caoutchouc,
gutta-percha, or gums, that could be vulcanized by the Goodyear
process, and converted from a soft into a hard, elastic material,
any use of that material for a dental plate might have been an
equivalent for the Cummings material, and an infringement of his
patent.
This construction of the patent is confirmed by the avowed
understanding of the patentee, expressed by him or on his half,
when his application for the original patent was pending. We do not
mean to be understood as asserting that any correspondence between
the applicant for a patent and the Commissioner of Patents can be
allowed to enlarge, diminish, or vary the language of a patent
afterwards issued. Undoubtedly a patent, like any other written
instrument, is to be interpreted by its own terms. But when a
patent bears on its face a particular construction, inasmuch as the
specification and claim are in the words of the patentee, it is
reasonable to hold that such a construction may be confirmed by
what the patentee said when he was making his application. The
understanding of a party to a contract has always been regarded as
of some importance in its interpretation.
In his letter to the Commissioner under date of July 30, 1855,
written by his attorney, after striking out all reference to
gutta-percha, he said:
"I beg the office not to consider that because gutta-percha has
been used heretofore with artificial teeth, Mr. Cummings's
invention is therefore the mere substitution of one substance for
another and a similar one. The vulcanizing process makes all the
difference, and changes the article of manufacture entirely."
So in his letter of the same date, he amended his specification
so as to make it read:
"I do not claim the use of gutta-percha, or of any material
which is merely rendered plastic by heat and hardened by cooling,
in the manufacture of sets of artificial teeth; but what I do claim
as my
Page 102 U. S. 228
invention and desire to have secured to me by letters patent is
the improvement in the manufacture of sets of mineral or other
artificial teeth, which consists in combining them with a rubber
plate and gums, which (after the insertion of the teeth) are
vulcanized by Goodyear's process, or any other process. . . ."
On a renewed application, Dr. Cummings was informed that the
office would not object to the admission of a claim limited to the
use of vulcanite or hard rubber. In response to this, he amended
his claim by inserting the word "hard" before "rubber," and also by
striking out the word "other" before the words "elastic material,"
in the claim as previously made, and substituting therefor the
words "vulcanite,
i.e., an," so as to make it read,
"forming the plate and gums in which the teeth are inserted in one
piece of hard rubber, or vulcanite,
i.e., an elastic
material." Thus the patent was granted. In view of this, there can
be no doubt of what Cummings understood he had patented, and that
both he and the commissioner regarded the patent to be for a
manufacture made exclusively of vulcanites by the detailed process.
We think this, to some extent, at least, tends to confirm the
conclusions at which we have arrived in interpreting the patent by
its own language. Indeed, we have heretofore expressed doubts
whether reissued letters patent can be sustained in any case where
they contain claims that have once been formally disclaimed by the
patentee or rejected with his acquiescence and he has consented to
such rejection in order to obtain his letters patent.
Leggett
v. Avery, 101 U. S. 256. If
these doubts be well founded and the claim of the reissued letters
now before us be, what these complainants insist it is, a claim for
the use of any other material than vulcanite or some substance
capable of vulcanization, another question might arise respecting
the validity of the reissue.
We have extended our remarks sufficiently upon this branch of
the case. It remains to inquire whether the manufacture by the
defendant of dental plates, out of the material known as celluloid,
or solid collodion, is an infringement of the Cummings reissue. We
think it is not.
Celluloid is a substance of a comparatively recent
discovery.
Page 102 U. S. 229
Whether it was known at the time Cummings made his invention, or
even at the time when his original patent was granted, we do not
care now to inquire. It is sufficient for this case that we
consider what it is. It is a compound of vegetable fiber,
cellulose, or gun-cotton. Undoubtedly it can be employed for
manufacturing dental plates, and as a base for artificial teeth.
Such a plate may have the fineness, lightness, and elasticity of a
plate made of hard rubber by the Cummings process, but it is a
substance very different from hard rubber, and it is incapable of
the same manipulation. It is not vulcanite, and neither it nor its
ingredients are capable of being vulcanized. It contains no sulphur
or rubber. None of its constituents are vulcanizing agents. Camphor
does not perform the function of sulphur. Under the action of heat,
its tendency is to soften the compounded mass, rather than to
harden it, as sulphur does rubber. When the ingredients of
celluloid are compounded, the product is hard, unlike caoutchouc or
gums generally, and heat softens, rather than hardens, it. When
employed in manufacturing dental plates, the process is wholly
unlike that employed in making hard rubber or vulcanite plates. It
is put into a mold, it is true, such as was known and in use before
the Cummings invention, but it is put in in a hard state, in its
natural condition, and not soft or plastic and capable of being
pressed around the teeth. The mold cannot be closed until heat is
applied. When that is applied, the jaws of the mold are gradually
screwed together as the celluloid softens, and when the jaws come
together, the plate is completed. The process requires pressure in
addition to heat in order to reduce the plate to shape and compress
it around the teeth. There is no heating for hours as is necessary
in the vulcanizing process. The work is done in a few minutes. When
allowed to cool, it is the same hard and bony substance it was
before its manipulation, and in this respect also it is unlike
vulcanite. It is obvious from all this that neither in the nature
of the material of which it is made nor in the process of
manufacture, which is an essential part of the Cummings invention,
as we have seen, is the celluloid plate substantially the same as
one made of hard rubber.
Nor is celluloid an equivalent for hard rubber, for the
reasons,
Page 102 U. S. 230
already suggested, that it is not capable of vulcanization and
that it cannot be made into a plate by the process prescribed by
Cummings. It may be conceded the patentee is protected against
equivalents for any part of his invention. He would be, whether he
had claimed them or not. But when a product arrived at by certain
defined stages or processes is patented, only those things can be
considered equivalents for the elements of the manufacture which
perform the same function in substantially the same way. The same
result may be reached by different processes, each of them
patentable, and one process is not infringed by the use of any
number of its stages less than all of them.
In view of these considerations, we are constrained to rule that
a celluloid dental plate is not an infringement of the Commings
patent. Celluloid is not an equivalent for the material which the
patent makes essential to the invention, and in the use of it for a
dental plate, the process which is inseparable from the invention
is not and cannot be employed.
Decree affirmed.