138 



Shiro Tashiro 



I have constructed two apparati, based on this principle, which 

 are especially adapted for the estimation of the output of carbon diox- 

 ide for very small biological specimens. With these apparati, one 

 cannot only detect easily a very small amount of gas, given off by a 

 small dry seed, or a small piece of a frog's sciatic nerve, but can also 

 estimate it with considerable accuracy. 



The apparatus shown in Fig. i 

 consists of two glass bulbs. The 

 upper bulb A, is a respiratory 

 chamber, having a capacity of about 

 15 c.c., which can be diminished to 

 9 c.c. by means of mercury. The 

 lower bulb B is an analytic chamber 

 with a volume of 25 c.c., which can 

 be made to 5 c.c. by filling up with 

 mercury. These two bulbs are con- 

 nected with a capillary stop-cock D. 

 The respiratory chamber is fitted 

 with a tight glass stopper, R, which 

 is connected to a three-way capillary 

 stop-cock C. This glass stopper is 

 so arranged that the chamber can 

 be sealed by putting mercury above 

 the stopper. 



The tubes are thick walled capillaries of about i mm. internal 

 diameter, excepting upturned tubes inside the bulbs, which should 

 be rather thin walled, especially at F and H, where it is widened to an 

 internal diameter of about 2 mm. It is important that the glass of 

 which these tubes are made should be of a quality not readily attacked 

 by barium hydroxide. 



The details of the method of procedure are as follows : 



The apparatus is first cleaned and dried. 4 The specimen is 



4 The apparatus is made in such a way that it can be cleaned and dried in 

 ten minutes without being taken apart. For this, the stop-cock D is closed and 

 E and L are opened. The arm at L is connected to the suction pump. Then 

 a little acidulated water is introduced through G. By closing E, and opening D 

 and G, the excess of water is drained off. Then the process is repeated with dis- 

 tilled water, alcohol, and alcohol ether. The last drying is completed by passing 

 a current of air through G while D is closed. 



FIGURE 1 

 One-third the actual size. 



