212 THE AMERICAN MONTHLY [July, 



dry and macerated bones, the other from fresh decalci- 

 fied bones. 



SECTIONS OF DRY BONES. 



Select a very white and dry bone, preferably an adult 

 long bone. Avoid those with yellowish or translucent 

 spots showing the presence of fat. . . .Fasten the bone 

 in a vice and with a fine saw cut a series of plates as 

 thin as possible, some longitudinal, some transverse. 

 Rub them between two punice stones, taking care to 

 turn the section occasionally and to keep it wet. When 

 thin enough, wash it and smooth it on a whetstone. The 

 best way is to hold the section by the finger tips and 

 move it to and fro. By Canada balsam it may be fas- 

 tened to a slide, or by gum to a cork, and so rubbed 

 down, the cement being dissolved away when the bone 

 is thin enough. . . . 



TO EXAMINE THE OSTEOBLASTS FILLED WITH AIR. 



Spread gum over both surfaces of a section and dry it 

 rapidly over a flame. Heat a little old balsam on a slide 

 and mount the section, cooling the balsam rapidly on a 

 cold stone or marble. The gum prevents the entrance 

 of the balsam into the corpuscles. 



TO STAIN OSTEOBLASTS AND CANALICULI. — This is M. 

 Ranveir's method and produces a true interstitial injec- 

 tion of the canaliculi and the oseous corpuscles. With 

 a scalpel scrape a section made as described. It is then 

 put in an alcoholic solution of aniline blue in a test-tube 

 closed by a cork pierced by a hole in which is placed a 

 tube a metre long. The solution is boiled on a water 

 bath for 5 or 6 hours, the alcoholic vapors condensing and 

 falling back to prevent the entire evaporation of the 

 fluid. The section is smoothed on both surfaces on a 

 whetstone wet with a solution of common salt. Mount 

 in neutral glycerine. 



