352 



RESPIRATION. 



[CH. xxiv. 



and to connect this tube by some gutta-percha tubing with a 

 introduced into the cork of a large bottle, the other end of the J having 

 attached to it a second piece of tubing, which can remain open or can be 

 partially or completely closed by means of a screw clamp. Into the cork is 

 inserted a second piece of glass tubing connected with a Marey's tambour 

 by suitable tubing. This second tube communicates any alteration of the 

 pressure in the bottle to the tambour, and this may be made to write on a 

 recording surface. 



There are various instruments for recording the movements of the chest by 

 application of apparatus to the exterior. Such is the stethograph of Burdon- 

 Sanderson (fig. 321 ). This consists of a frame formed of two parallel steel bars 

 joined by a third at one end. At the free end of the bars is attached a leather 

 strap, by means of which the apparatus may be suspended from the neck. 

 Attached to the inner end of one bar is a tambour and ivory button, to the 



I I 1 



Fig. 322. Tracing of the normal diaphragm respirations of rabbit, a, with quick move- 

 ment of drum. 6, with slow movement. The upstrokes represent inspiration ; the 

 downstrokes, expiration. To be read from left to right. (Marckwald.) 



end of the other an ivory button. When in use, the apparatus is suspended 

 with the transverse bar posteriorly, the button of the tambour is placed on 

 the part of the chest the movement of which it is desired to record, and the 

 other button is made to press upon the corresponding point on the other side 

 of the chest, so that the chest is, as it were, held between a pair of callipers. 

 The tambour is connected by tubing and a f-piece with a recording tambour 

 and with a ball, by means of which air can be squeezed into the cavity of 

 the tympanum. When in work the tube connected with the air ball is 

 shut off by means of a screw clamp. The movement of the chest is thus 

 communicated to the recording tambour. 



A simpler form of this apparatus consists of a thick india-rubber bag of 

 elliptical shape about three inches long, to one end of which a rigid gutta- 

 percha tube is attached. This bag may be fixed at any required place on 

 the chest by means of a strap and buckle. By means of the gutta-percha 



