referring to the drawings and particularly to fig1 and 3 , the patient mouthpiece apparatus of the form of the invention there illustrated is generally designated by the numeral 12 . this embodiment apparatus of the invention is adapted for use in connection with respiratory equipment for supplying fluids such as liquids and gases to a patient through a conduit which interconnects the remotely located respiratory equipment with the mouthpiece portion of the apparatus . as best seen by referring to fig1 the apparatus comprises a first , or mouthpiece portion , 14 and a second , or mouthpiece encapsulation , portion 16 . the mouthpiece portion includes a generally tubular shaped body 18 having an elliptical shaped fluid passageway 20 therethrough . body 18 has first and second ends generally designated as 22 and 24 . second end 24 is adapted to be interconnected with the remotely located respiratory equipment and connector means are provided for that purpose . in the present embodiment of the invention , the connector means comprises a pair of longitudinally spaced , radially outwardly extending ribs 28 which circumscribe body 18 . when the conduit which interconnects the mouthpiece with the remotely located respiratory equipment comprises a yieldably deformable plastic tube the open end of the plastic tube is closely receivable over and held in place by ribs 28 . the conduit may also comprise a filter unit in which case the inlet of the filter unit is receivable over and held in place by ribs 28 . disposed within the central portion of body 18 is an internal saliva entrapment cavity generally designated by the numeral 30 . referring particularly to fig1 and 3 , it is to be noted that a first generally planar wall 32 circumscribes body 18 at a location intermediate the first and second ends thereof . planar wall 32 is generally elliptical in shape and , as will presently be described , is closely receivable within the open end of the skirt portion of the encapsulating means of this form of the invention . a second , generally elliptically shaped curved wall 34 is located proximate the first end of body 18 . wall 34 is specially configured to be comfortably received within the patient &# 39 ; s mouth . the novel shape of wall 34 uniquely permits the mouthpiece portion 14 to be held comfortably and securely in place within the patient &# 39 ; s mouth during the introduction of fluids from the remotely located respiratory equipment . while various other configurations of wall 34 can be used , the generally elliptical shape shown in fig1 of the drawings has proven to be quite successful in clinical tests . the second , or mouthpiece encapsulation , portion , of the apparatus comprises a hollow skirt portion 38 which is closely receivable over walls 32 and 34 of mouthpiece portion 14 . as best seen by referring to fig3 skirt portion 38 has a first end 38a which is sealably closed by an integrally formed end closure wall 40 . the open end 38b of the skirt 38 is configured so as to closely and sealably receive wall 32 of the mouthpiece portion in the manner shown in fig3 and 4 . in fig5 the cross - section of the skirt portion is elliptical shaped . in this regard , it is to be noted that skirt portion 38 tapers slightly outwardly from wall 40 so that as the mouthpiece portion 14 is inserted into the encapsulation portion , wall 32 will tightly engage the internal wall of skirt 38 at a location slightly inboard of the open end 38b . with this construction , the mouthpiece portion 14 will be secureably sealed within , and encapsulated by , the encapsulation portion 16 . another important feature of the apparatus of the invention comprises the sealing means of the device for sealably closing the fluid passageway 20 of body 18 . in the present embodiment of the invention the sealing means comprises an inwardly tapering closure member 42 which has a cross - section that is elliptical shape end is integrally formed with , and extends inwardly of , wall 40 in the manner shown in fig3 , and 5 . closure member 42 is closely receivable within passageway 20 of body 18 and , due to its inwardly tapering configuration , will sealably engage the inner wall 20a of passageway 20 so as to positively seal off the saliva entrapment chamber 30 and effectively prevent any leakage of saliva from the device . the apparatus of the invention can be constructed of a variety of materials . however , in practice both the first and second portions of the device are integrally formed of a moldable plastic material such as polyethylene or polypropylene . in using the apparatus of the present invention to safely seal off a possibly contaminated mouthpiece relative to atmosphere , encapsulating portion 16 is placed over mouthpiece portion 14 while portion 14 is still connected to the respiratory equipment . because the patient has breathed inwardly and outwardly through the mouthpiece , varying amounts of saliva have become entrapped in the cavity portion 30 and within the passageway 20 of the mouthpiece portion . as the encapsulating portion is placed over and urged into engagement with the mouthpiece portion , the sealing means or closure member 42 will be closely received within passageway 20 so as to sealably close the passageway and isolate the saliva entrapment chamber from atmosphere . at the same time that the closure member 42 is being forced into sealing engagement with the inner wall of passageway 20 , closure wall 32 of the mouthpiece is being moved into sealable engagement with the inner wall of the skirt portion 38 . the fit of the closure member 42 to passageway 20 and of wall 32 to skirt 38 is such that frictional forces will securely hold together the first and second portion of the apparatus . in this matted position , the interior of the mouthpiece containing the patient &# 39 ; s saliva is effectively sealed relative to atmosphere . further , since the encapsulating means of the apparatus completely encapsulates that portion of the mouthpiece section which has been in the patient &# 39 ; s mouth , spread of contamination from the surfaces which have been in contact with the patient &# 39 ; s mouth is also effectively prevented . another important aspect of the apparatus of the present invention resides in its pretreatment during interconnection of the mouthpiece portion with the auxiliary respiratory equipment , such as a piece of breathing tube , bacterial filter or the like . so long as the protective shield or encapsulating portion is in position around the mouthpiece section , the apparatus can be safely handled by the technologist without fear of contaminating the mouthpiece . more particularly , end 24 of the mouthpiece can be interconnected with the conduit or bacterial filter , which forms a part of the remotely located respiratory equipment , without fear of contamination of those surfaces of the mouthpiece which are to be received within the patient &# 39 ; s mouth . this unique feature of the apparatus effectively prevents the spread of contamination from the technologist to the patient . having now described the invention in detail in accordance with the requirements of the patent statutes , those skilled in this art will have no difficulty in making changes and modifications in the individual parts or their relative assembly in order to meet specific requirements or conditions . such changes and modifications may be made without departing from the scope and spirit of the invention , as set forth in the following claims .