Page 630 - My FlipBook

628 EXTRACTION OF TEETH.

administered to the patient. J>y a turn of tiic levers r/ and /(Fig. 570)
any gradation of" the gases may be obtained, from jiiire nitrons oxid on
the one iianil to pure oxygen on tlie other. Tiie eonstruction of the
apj>aratus is such as to better withstand the climatic conditions than the
Hewitt ai)paratns. A brief description will suffice to show the working
of the apparatus.
There are two cylinders, one containing compressed nitrous oxid and
the other compressed oxygen.
Two bags, one of black material containing the nitrous oxid, the
other of red material containing the oxygen.
The key to each cylinder (see b and c) opens the valve and allows
the gas to pass into its respective bag.
By opening the valve (see /) of the nitrons oxid bag the gas passes
into the mixing-chamber, from which it flows through the covered rub-
ber tube to the inhaler.
When it is desired to combine oxygen with nitrous oxid, open
gauged valve (see a, c) to the oxygen bag ; this will admit the oxygen
into the mixing-chamber. Both gases Avill pass through the tube to
the inhaler.
The proportion of oxygen used will be determined by the degree
to which the gauged valve is opened.
By closing the valve of the nitrous oxid bag, oxygen can be given
separately.
Similar results are obtained w'hen air is admitted, instead of oxygen,
to the patient during the nitrous oxid administration. The details of
this procedure are set forth in the following chapter.