

1920] 



MAGNESS— INTERCELLULAR SPACES 



309 



fitted with a ground glass stopper (C) in which is sealed a capillary 

 tube. The flare in the top of the cylinder should be sufficient to 

 allow the stopper to set well down (as illustrated), in order to per- 

 mit a mercury seal above the 

 stopper. The capillary tubing is 

 bent around in the manner shown, 

 in such a way that the tip can be 

 immersed in a vessel of mercury 

 (D). Glass stopcocks (E and F) 

 must be in the positions shown. 

 It is especially important that 

 the cock F be as indicated, rather 

 than directly above the cylinder, 

 for by the former arrangement 

 any small leak about the cock 

 can quickly be detected. Cocks 

 and stopper should be kept well 



Fig. t 



coated with heavy desiccator grease. The proper dimensions for 

 the cylinder (B) will obviously vary with the type of tissue being 

 examined, and the volume of this tissue necessary to secure a gas 

 sample adequate for an analysis. For work with apple and potato 

 tissue, a cylinder 6 inches long and 1 inch inside diameter has been 

 found very satisfactory. 



