Improvements in Catheters.
Year: 1895

page_text: Date of Application, 12th July, 1895
Complete Specification Left, 10th Apr., 1896-Accepted, 16th May, 1896
Improvements in Catheters.
We, ALFRED WALSH, of 23 Bartholomew Square, and CHARLES MAW,
JOHN THOMPSON, and CHARLES TRENTHAM MAW, of the Firm of S. Maw, Son,
& Thompson, of 7 to 12 Aldersgate Street, both in the City of London, Surgical
Instrument Makers, do hereby declare the nature of this invention to be as
follows:-
This invention has for its object improvements in catheters.
Gum elastic catheters as at present made consist essentially of a tube of woven
fabric stiffened by the application of a fluid preparation of oil and gum. Heretofore
the interior of such catheters has been rough the fabric appearing on the inner
surface.
This is objectionable as bacteria are likely to be harboured in the irregularities
of the surface and perfect cleansing is very difficult if not impossible.
According to this invention after the catheter has been made in the ordinary
way, the fluid gum elastic is poured through it so as to thoroughly coat the
inner surface, then after a sufficient time has been allowed for the composition
to set, a highly polished metallic wire is passed through and used to smooth the
surface and finally when the interior coating is hard it is ground and polished
by the aid of a wire burnisher and polishing powder. Thus the inner surface of
the catheter is as highly finished as the exterior.
Dated this 11th day of July 1895.
ALFRED WALSH.
CHARLES MAW.
J. THOMPSON.
C. TRENTHAM MAW.
Improvements in Catheters.
We, ALFRED WALSH, of 23 Bartholomew Square, and CHARLES MAW, JOHN
THOMPSON, and CHARLES TRENTHAM MAW, of the Firm of S. Maw, Son,
& Thompson, of 7 to 12 Aldersgate Street, both in the City of London, Surgical
Instrument Makers, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :—
This invention has for its object improvements in catheters.
Gum elastic catheters as at present made consist essentially of a tube of woven
fabric stiffened by the application of a fluid preparation of oil and gum. Heretofore
the interior of such catheters has been rough the fabric appearing on the inner
surface.
This is objectionable as bacteria are likely to be harboured in the irregularities
of the surface and perfect cleansing is very difficult if not impossible.
According to this invention we produce a highly polished gum elastic surface in

page_text: the interior of the catheter so that the foundation tube of woven fabric is entirely
enveloped and enclosed within the gum elastic.
+
We make the improved catheters in the following way. :-The woven silk tube
which serves as the foundation is stretched upon an iron wire, the wire being
inserted into it, then as usual the woven tube is coated with semi-fluid gum
elastic.
The so called gum elastic is a composition consisting of copal varnish, burnt or
highly boiled linseed oil and a small quantity of linseed oil in its natural or
unboiled state. When the coating of gum elastic has hardened the wire is
withdrawn from the woven tube. Next another coating of gum elastic is applied
to the exterior of the woven tube and after this in turn has hardened it is
followed by other coatings and so on, coating after coating being applied say daily,
until the exterior covering of gum elastic has attained to nearly its full thickness.
Each successive coating is hardened by exposure in an oven heated by steam to a
temperature of 170 to 180 Fahrenheit or thereabout.
All these operations are such as are usual in the manufacture of catheters. At
this stage, the coating for the interior of the catheter is commenced by pouring
the gum elastic through it and allowing it to drain out. An exterior coating of
gum elastic may be applied at the same operation. In this way the catheter
receives about six internal coatings, each coating being hardened before the next
is applied. Finally the smoothing and polishing of the surfaces has to be
performed; for the exterior this is done in the usual way on a travelling band
with polishing powder consisting of rouge and pumice. The interior is smoothed
and polished with the same polishing powder mixed with a little oil, it is applied
by means of a wire and the wire is worked about within the catheter by hand
continually until no roughness or unevenness is discernable.
In catheters thus made every part of the surface both within and without is of
the non-absorbent gum elastic and the woven foundation tube is completely and
inaccessibly buried in the gum elastic. The smooth impervious surface of the gum
elastic affords no shelter for bacteria and it can be cleaned with facility.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
A gum elastic catheter made substantially as described and having its interior
as well as. its exterior surface of smooth or polished gum elastic.
Dated this 4th day of March 1896.
ALFRED WALSH.
CHARLES MAW.
J. THOMPSON.
C. TRENTHAM MAW.
ALFRED WALSH.
CHARLES MAW.
J. THOMPSON.
C. TRENTHAM MAW.