referring now to fig3 and 4 , reference numeral 10 designates a hollow bag - like water collection body formed of soft and resilient rubber such as latex rubber , the water collection body having a boat - like shape in plane . the water collection body 10 is sufficiently elastic and resilient to have a self - restoring capability when it is pressed and collapsed . the configuration of the body 10 is not limited to that shown in the embodiment but other spherical or elliptic configurations or the like may be employed . the water collection body 10 is provided with a number of orifices 11 and 12 extending parallel to a long axis of the ovoid body . the orifices 11 provided on the front side of body 10 with respect to the mouth of a patient , are positioned to face outwardly of the mouth during use and are made slightly larger than the orifices 12 provided on an opposite rear side , positioned to face the throat . the orifices are large enough to easily gather water in collection body 10 and to minimize pain caused by the attraction of the body if it contacts tissue of the deep portion in the mouth . the water collection body 10 is particularly provided at one end thereof with a mounting hole 13 as shown in fig4 . a member having an approximately u - shape with a mounting portion 14a inserted into the mounting hole 13 forms a water discharge tube 14 . in this embodiment , the water collection body 10 is mounted at a distance from the curved position of the water discharge tube which is determined so that the mounting portion 14a of the water discharge tube 14 reaches a position in the deep portion of the mouth where the water collection body 10 is best placed . a shape - retention member 15 having an approximately arch - shape particularly as shown in fig4 is mounted on the end of a portion of the water collection tube 14 which is inserted into the water collection body 10 to maintain its original shape and to prevent the water collection body 10 from collapsing during the discharge of water . the shape - retention member 15 is required when the water collection body 10 is formed of a soft material and is not sometimes required when the water collection body 10 is more resilient . a connecting portion 14b for connecting a water discharge hose ( not shown ) is provided on the other end of the water discharge tube 14 , particularly as shown in fig3 the connecting portion 14b being provided with air intake means 16 . the air intake means 16 comprises a vent hole 14c provided in the water discharge tube 14 and an air adjusting ring 17 in the form of a ring rotatably fitted on the outer periphery of the tube . the air adjusting ring 17 is provided with an air port 17a in registration with the vent hole 14c . the air intake means 16 is not required when the attraction force due to suction is weak . in the embodiment in use , the water collection body 10 is placed just over the inlet of the throat in the deep portion of the mouth of a patient , as shown in fig4 and a vacuum pump ( not shown ) is used to always discharge the mixed water during treatment . fig5 shows another embodiment , which is the same as the previous embodiment in that the water collection body 20 is provided with a plurality of orifices 21 . this embodiment is different from the previous embodiment in that the water collection body 20 itself is formed of hard or semi - hard material such as polyethylene , acryl , etc . the water discharge pipe 22 has a mounting portion 22a which is bent toward the water collection body 20 from a u - shaped portion of the pipe 22 , a mounting portion 22a is inserted into and secured to a mounting hole 23 provided on one side of the water collection body 20 . of course , the mounting hole 23 would not be required in the case where the water collection body 20 and the water discharge tube 22 are integrally molded . in this embodiment , as shown in fig5 in use , the water discharge tube 22 is inserted into the mouth along a row of teeth 24 , and the water collection body 20 can be easily arranged in the inlet of the throat in a central deep portion of the mouth . in fig3 and 4 , the mounting the water discharge tube on the water collection body can be embodied as in fig5 . fig6 to 8 show another embodiment . as shown , a water collection body 30 made of synthetic resin which is soft but resilient to have shape retention , is provided at the rear with two rows of plural orifices 31 and provided at the front with two rows of middle orifices 32 having larger diameter than the orifices 31 . a tubular mounting body 33 projects on one side of the water collection body 30 , and one end of a water discharge tube 34 having an approximately u - shape and a relatively large diameter is slidable and rotatably inserted into and secured to the tubular body 33 . the water discharge tube 34 is connected to a mounting tube 36 of which the other end is connected axially rotatably to one end of an attitude control tube 35 having an approximately v - shape . the attitude control tube 35 has an other end to which is rotatably connected a tube connection tube 37 , and a tube connected to vacuum ( not shown ) is connected to the tube connection tube 37 . the water discharge tube in this embodiment is connected to a vaccum having a powerful attraction force through a vacuum hose . however , since the water collection body 30 is provided with the middle orifices , the water collection body 30 is not collapsed by the attraction force . fig9 to 11 show still another embodiment in which shape , size and material of the water collection body are the same as those shown in fig6 to 8 . however , this water collection body 40 is provided at the front and rear with two rows of orifices 41 having approximately the same diameter . one end of a water discharge tube 43 having the same diameter as that of a conventional saliva discharge tube and having an approximately u - shape in plane is inserted into and secured to a mounting tubular body 42 having a smaller diameter than that of the previous embodiments . with this arrangement , since all the orifices have the same diameter , even if the water collection body is connected to the saliva discharge tube merely having a weak attraction force , it is possible to sufficiently discharge water in the deep portion in the mouth . fig1 to 14 show another embodiment . also in this embodiment , the shape , size and material of a water collection body 50 are the same as those shown in fig6 to 8 but the water collection body 50 is provided only on one side thereof with orifices 51 . moreover , the water discharge tube 53 is inserted into the water collection body until it is near the orifice 51 . with this arrangement , even if a mounting tube 52 of the water collection body 50 is connected to a water discharge tube 53 having the same diameter as that of a conventional saliva discharge tube merely having a weak attraction force , it is possible to sufficiently discharge water and the water collection body is not collapsed by the attraction force despite the small number of orifices . fig1 shows another embodiment , in which a water discharge tube 63 itself is flexibly bendably provided on a mounting tube 62 of a water collection body 60 provided on one side thereof with orifices 61 . with this arrangement , there is an advantage that the position of the water discharge tube ( not shown ) connected to the water discharge tube 63 during treatment of teeth can be freely changed without obstruction . fig1 and 17 show an embodiment of the invention where the saliva discharge tube 100 is slidably mounted in a handle portion 120 connected to a water suction portion 130 of a water suction body 110 which is positioned within an ovoid , edge - less , smooth walled un - corrugated water collection body 150 . water suction portion 130 has openings 160 near its lower end which communicate with the interior of body 150 which has four rows of orifices 180 . portion 130 also has an upper air intake opening 170 . handle portion 120 is slidably and rotatably mounted in a mounting tube 190 forming part of the body 150 . tube 100 is also slidably and rotatably mounted within handle portion 120 .