referring now to fig3 there is shown a surgical sponge generally designated 10 comprising a sheet 12 of an absorbent material , e . g ., a low - count open - mesh gauze or washed gauze fabric , such as woven cotton . the sheet 12 has a plurality of folds defining a multiple ply configuration of the sponge 10 . the sponge 10 has an elongated visually detectable element 14 comprising a pair of twisted strands 16 and 18 which have different colors . one of the strands 16 has a color which contrasts with the color of the sheet 12 , and the other of the strands 18 has a color which contrasts with the color of blood for a purpose which will be described below . in one form , the one strand 16 may have a color such as blue or green , and the other strand 18 may have a color such as white . the strands 16 and 18 may be constructed from a blood repellant material such as polyvinylchloride . in a preferred form , the element 14 is heat - bonded to an inner surface of an outer layer 20 of the folded sheet 12 such that the element 14 is visible through the open - mesh sheet 12 , thus reducing the possibility of scratching of delicate tissue by the element 14 . in one form , the strands 16 and 18 may be impregnated with barium sulphate in order to make the strands 16 and 18 radiopaque . in an alternative form , the strands 16 and 18 are not radiopaque , and the sponge 10 may have a separate radiopaque element 22 located in the folded sheet 12 , such as by impregnating the element 22 with barium sulphate . an apparatus 23 for forming the visually detectable element 14 on the sheet 12 is illustrated in fig1 and 2 . as shown , the apparatus 23 has a source 24 of the first strand 16 , such as a bin , and a source 26 of the other strand 18 , such as a bin . the strands 16 and 18 are removed from the sources 24 and 26 , respectively , and are passed through a central opening 28 in a rotating guide wheel 30 . in an alternative form , the strands 16 and 18 may be extruded from extruders 17 and 19 , respectively , and may be passed to the guide wheel 30 . the guide wheel 30 may be driven by a suitable motor 32 and an intermediate rotatable wheel 34 which is driven by the motor 32 . with reference to fig2 the guide wheel 30 has a pair of spring clips 36 and 38 which are biased together . as shown , after the strands 16 and 18 pass through the opening 28 , the strands 16 and 18 are frictionally and slidably received between the clips 36 and 38 which twist the strands 16 and 18 about each other into the element 14 . with reference to fig1 and 2 , the sheet 12 is passed over a rotatable wheel 40 , and then between a rotatable anvil wheel 42 and a rotatable bonding wheel 44 which pull the sheet 12 between the wheels 42 and 44 . the anvil wheel 42 may be driven by a suitable device such as a motor 46 . the bonding wheel 44 may be driven and heated by a suitable device such as a motor and heating device 48 . thus , the sheet 12 is moved between the wheels 42 and 44 in a direction as indicated by the arrow in the drawings . the twisted strands 16 and 18 are passed from the guide wheel 30 , and are placed against the sheet 12 . the twisted strands 16 and 18 comprising the element 14 are then passed through the wheels 42 and 44 where the wheel 44 heats the element 14 , and bonds the element 14 to one surface of the sheet 12 , after which the element 14 passes with the sheet 12 from the wheels 42 and 44 . finally , the sheet 12 with the element 14 is cut and folded into the configuration of the surgical sponge 10 previously described in connection with fig3 . in use , a number of the surgical sponges 10 are supplied to the personnel in an operating room for use during surgery . one of the persons on the operating team counts the sponges before placement in an incision , and also verifies that the element 14 is correctly in place on the sponges 10 . in this regard , the one strand 16 with the color which contrasts with the color of the sheet 12 facilitates inspection of the existence of the elements 14 on the sponges 10 . after counting of the sponges and inspection of the elements 14 , the sponges 10 are placed in an incision in a patient &# 39 ; s body during surgery . after surgery has been completed , the sponges 10 are removed from the incision , and the second strand 18 having a color which contrasts with the color of blood significantly enhances visibility of the sponges 10 in the incision in order to minimize the possibility that one of the sponges 10 may be left in the patient &# 39 ; s body after surgery has been completed and the incision is closed . another embodiment of the present invention is illustrated in fig4 in which like reference numerals designate like parts . in this embodiment , the element 14 has a first longitudinal part 50 of a color which contrasts with the color of the sponge , such as green or blue , and an integral second longitudinal part 52 of a color which contrasts with the color of blood , such as white . the parts 50 and 52 of the element 14 are coextruded from extruder 54 . the element 14 may be passed directly to the wheels 40 and 42 of fig1 thus bypassing the guide wheel 30 , or may be passed through guide wheel 30 to give a barber pole effect . the foregoing detailed description is given for clearness of understanding only , and no unnecessary limitations should be understood therefrom , as modifications will be obvious to those skilled in the art .
an apparatus for forming an elongated visually detectable element on a sheet of absorbent material comprising , a device for extruding at least one colored strand , and a device for placing the strand on the sheet .