1895.] MICROSCOPICAL JOURNAL. 237 



Sections. — Select the pig's liver, because the lobules 

 are clearly circumscribed by connective tissue, especially 

 at the surface, from which take the pieces to be sec- 

 tioned. To prevent pressure of the part to be cut, re- 

 move a cube by a very sharp razor with no pressure of 

 the fingers and use it for sectioning. 



Fixing. — We do not recommend alcohol, but, if used, 

 proceed thus : A cube of one half centimetre is put in 

 absolute alcohol for twenty-four hours. Wash in water 

 for half an hour, transfer to gum (twenty-four hours), 

 to 95° alcohol (twenty-fcur to forty-eight hours). Sec- 

 tion, stain in picro-carmine, mount in glycerine. But 

 osmic acid is the fixative par excellerice for the liver. 

 Take a strip 1 mm, long, put it in 3 or 4 cc. of 1 per 

 cent osmic acid for twenty-four hours. Wash in water 

 for twelve hours, harden in gum and alcohol. Section, 

 free from gum, stain in alum carmine and mount in gly- 

 cerine. Picric acid may be used for these sections to 

 show the glycogenic material. A piece 1 mm. on a side 

 is placed, still warm, in 50 grammes of the aqueous 

 solution of picric acid for twenty-four hours. Harden 

 in alcohol and put the sections in water till the yellow 

 color is gone. Stain. Ammonia bichromate (2 per 

 cent) is very useful for fixing small pieces one half to 

 one centimetre thick. Use a large amount of the solu- 

 tion (150 to 200 cc), and renew it once or twice. After 

 a week's sojourn in the bichromate, wash in water for 

 twenty-four hours, harden in alcohol and gum. The 

 sections, freed from gum, should be stained in haemat- 

 oxylin and eosine and mounted in balsam. 



Capillary Injection. — The vascular network may be 

 studied in the liver of the rat. After injection, treat a 

 small piece by bichromate for eight days, then by gum 

 and alcohol, make sections transversely and perpendicu- 



