380 



THE AMERICAN MONTHLY 



[Dec 



appliance and moving the shoulder slightly, perhaps an 

 iiicli. tlip instrument is placed directly over the foreign 



substance and brought witliin the parallelism of the 

 rays. Again tlie India ink brush is brought into requi- 

 sition and another cross-section indicated, intersecting 

 the other at some point on the surface. 



