HAND SPIROMETER. 



79 



oft 



C 



F 



w 



This form of apparatus is exactly the same in principle as that of the 

 laboratory type, but it has a wider range of application because of its 

 portability. It has recently been more generally used in this labora- 

 tory than the larger form, particularly in the analyses of samples of 

 alveolar air. 1 Both forms of apparatus are recommended because of 

 the accuracy with which gas analyses can be D 



made. 



HAND SPIROMETER. 



In connection with many tests of respiration 

 apparatus, some method for imitating the 

 respiration of man was found necessary. A 

 small leather bellows, with the intake valve 

 sealed up, was first employed. This was 

 attached to the opening of either a pair of 

 valves or one of the forms of respiration appa- 

 ratus, and an attempt made to simulate respi- 

 ration, but air-tight closure could not be 

 obtained. The success of the spirometer of 

 the Benedict respiration apparatus 2 suggested 

 the construction of a smaller form for the pur- 

 pose, which could be operated by hand. A 

 diagram of the hand spirometer is shown in 

 figure 33. 



In this apparatus a heavy copper cylinder, 

 A, is inverted in a double-walled annular bath 

 of water or oil. From an opening, B, in the 

 top of the cylinder forming the inner wall of 

 the bath a tube leads down through the bot- 

 tom of the spirometer, then makes a right- 

 angle joint, the lower end of the tube being 

 open to the air at C. For raising and lower- 

 ing the bell of the spirometer, a long handle 

 is provided which runs through an opening 

 in the top crosspiece of the frame attached 

 to the spirometer. The height to which the 

 bell may be raised is regulated by means of 

 a set-screw, E, which is placed upon the rod 

 of the handle, thus determining the amount 

 of air put into or out of the spirometer. The 

 total content of the spirometer is about 1 liter. 

 The height of the bell is 20.5 cm. and the 

 diameter of the cross-section 8 cm. The whole 

 apparatus is mounted on a small block and 

 thus can be set up on any flat surface wher- 

 ever needed. 



> 



F 



D 



Fig. 33. — Hand spirometer. 

 The apparatus consists of a 

 copper cylinder, A, immersed 

 in a double-walled annular 

 bath. An opening, B, in the 

 top of the inner cylinder of the 

 bath, connects with the out- 

 side air through the tube, C, 

 which makes a right-angle 

 bend at the bottom. The bell, 

 A, is raised and lowered by the 

 handle, D, the height to which 

 it is raised being controlled by 

 the set screw, E. 



Wiggins, Am. Journ. Physiol., 1914, 34, p. 114. 



2 See p. 37. 



