236 THE AMERICAN MONTHLY [Aug, 



Dissociatio7i. — Take a piece of gland one or two mm. 

 thick, and put it for 24 hours in a few cc. of the J alco- 

 hol. It is then only necessary to agitate the piece in a 

 drop of the s alcohol to obtain magnificent cells perfectly 

 isolated. Stain in picro-carmine. Cover after partly 

 drying, as already described. 



Sections. — (1) A piece of gland is fixed for 24 hours 

 in strong alcohol, hardened in gum and alcohol, sec- 

 tioned, stained in picro-carmine, mounted in glycerine. 

 This method gives splendid preparations of mucous 

 glands. 



(2) A piece of gland is put in osmic acid for 12 hours, 

 washed, hardened in gum and alcohol. Examine the 

 sections in water, or stain well in alum carmine, and 

 mount in glycerine. 



(3) Place a piece in ammonia bichromate (2 per cent) 

 for eight days, wash, harden in gum and alcoliol ; stain 

 sections in hsematoxylin and eosine ; mount in balsam. 



(4) Fix in bichromate, inject the blood vessels by the 

 Prussian blue mass, stain in hsematoxylin, mount in 

 balsam. (This is the first time the author has recom- 

 mended the use of balsam, always preferring dammar.) 



THE LIVER. 



Take the liver of an animal dead for some hours. Cut 

 out a piece and scrape it with a scalpel. Place the re- 

 sult on a slide with a drop of picro-carmine; you will 

 see a crowd of isolated cells like little polyhedral 

 blocks, with blunt borders. These are the elements 

 modified by cadaveric changes. To see the cells fixed 

 in the living state, macerate in the I alcohol a small 

 piece taken from a recently killed animal and scrape it 

 as described. Another method, more difiicult but infin- 

 itely better, is to place a small cube of liver (1 mm. 

 square) in L per cent osmic acid, and in 24 hours disso- 

 ciate on a slide in a drop of water. 



