12 



OPERATIVE TECHNIQUE. 



one hand and withdrawn, the instrument held firmh- in the other hand 

 is then introduced into the mouth and pushed between the upper and 

 lower rows of molars as far as it will go. The instrument should be 

 steadied in position with one hand, whilst with the other the examina- 

 tion is made. As the operator himself controls the gag, he has ample 

 warning to withdraw his hand in case of danger. Haussmann's mouth- 

 gag for horses (Figs. 20 — 22) is probabh- the best and most convenient. 



Fig. 20. — Haussmann's mouth-g.'ig- (openl. 



Fig. 21. — Rubber-covered 

 plates for operations on 

 incisor teeth. 



Fig. 22. — Haussmann's mouth-gag ^closed). 



Whether it \\as first invented by Haussmann or by an unknown 

 American is open to question. In Germany it is known as Hauss- 

 mann's ; in England as the American mouth-gag. It possesses the 

 important advantages of pressing only on the incisor teeth, and there- 

 fore is not liable to injure the mouth, however long its application ; it 

 leaves the cavity of the mouth entirely clear, a great point when 

 operating on teeth ; it is relaxed in a moment, and as readily extended 



