Abstract
1. The pressure change in the oral cavity by the normal respiration was about 2mm. H2O.
2. The so-called cleaning motion was divided into three types according to the feature in the pressure change and operculars movement (see text).
3. The once elevated or lowered pressure level by the so-called cleaning motion recovers gradually in the course of several cycles of the following normal respiretion.
4. By the spitreflex a sudden ascent and descent down to the normal level was recorded.
5. The removal of the oral valves resulted in almost 50 % decrease of the pressure change. That of the opercular valves did not produce any remarkable change.
6. From results above the following was concluded.
a) The name “cleaning” is not suitable for this motion.
b) The pressure within the oral cavity does not stationarily balance with that of the outermedium during the normal respiration.
The author wishes to express his heartful thanks to Prof. SUYEHIRO for constant guidance in the course of this work. Thanks are also due to Assist. Prof. HIBIYA for valuable suggestions.
