532 



JOHN R. MUELIN 



7. 



the two sides of the opening are thick rubber projections which may be 

 held between the teeth. Sometimes the mouth-piece is supplemented by a 



band of rubber tied 

 around the head and 

 pressing against the 

 lips from the outside. 

 In the use of this device 

 the nose must of course 

 be closed by some form 

 of clip or clamp (Reg- 

 yl , nard) (Fig, 10). 



Glass nose-pieces 

 have been described by 

 Tissot and these have 

 been improved by Car- 

 penter (a). A pneu- 

 matic nose-piece de- 

 scribed by F. G. Bene- 

 dict (d) (Fig. 11) is 

 much to be preferred to 

 the all-glass construc- 

 tion. They can be made 

 very secure by inflation 

 of the pneumatic por- 

 tion particularly if the 

 outer rubber which fits 

 against the nose is cov- 

 ered with mucilage. 

 Many subjects, how- 

 ever, find the nose- 

 pieces quite uncomfort- 

 able and prefer the 

 mouth-piece described 

 above. Benedict him- 

 self has recently recom- 

 mended the mouth- 



Fig. 10. 

 clip attached. 



Mouth-piece of Denayrouse with nose 

 (1) brass tube connecting to apparatus; 

 (2) collar supporting stand (3) which in turn sup- 

 ports nose piece; (4) brass collar; (5) frame of nose- 

 piece with adjusting screw for regulating pressure on 

 nose; (6) nose pads; (7) rubber of mouth-piece which 

 fits in between teeth and lips ; ( 8 ) opening from mouth- 

 piece into brass tube; (9) rubber lugs which may be 

 grasped between the teeth ; ( 10 ) rubber tube continuous 

 with mouth-piece; (11) strap for holding mouth-piece 

 firmly in place. 



piece with a clinical 

 respiration apparatus in preference to the nose-piece (Benedict and Col- 

 lins). When nose-pieces are used the mouth should be sealed shut with an 

 adhesive tape. 



Various types of masks have also been used from the crude copper mask 

 covering the entire face employed by Lavoisier, to the modern so-called half 

 mask employed in mine rescue work. The gas masks, perfected from force 

 of necessity during the recent war, have also found a useful field in con- 



