1895.] MICROSCOPICAL JOURNAL. 235 



at one end and fill with filtered fresh lemon juice. Li - 

 gate at the other end and place the distended intestine 

 in a few cc. of lemon juice. In five minutes cut the in- 

 testine and wash ra[)idly in water. Put it in the 1 per 

 cent gold chloride for 20 minutes, wash rapidly and re- 

 duce the gold in the i formic acid. Make the following 

 preparations : — 



(1) Detach with the forceps the longitudinal muscular 

 layer, which will remove with it the serous coat and the 

 plexus of Auerbach. Mount fiat in glycerine. 



(2) Macerate for 24 hours in the ^ alcohol a piece im- 

 pregnated by gold; with a scalpel scrape away the villi 

 and the glandular layer; in the same way remove the 

 muscular coat. There remains a transparent membrane 

 speckled with violet. It is the sub-mucous layer with 

 the plexus of Meissner. Mount flat in glycerine. 



(3) Make sections perpendicular to the surface of a 

 piece impregnated by the gold. Harden in gum and 

 alcohol. These preparations should show the relations 

 of the nerve fibres to one another. 



THE TEETH. 



Sectio7i of a fresh tooth. — This is a wearisome opera- 

 tion which may be avoided by buying the beautiful pre- 

 parations of the dealers. The writer has had no experi- 

 ence in preparing fresh teeth. 



Section of a decalcified tooth. — Suspend a tooth by a 

 thread in Kleinenberg's liquid (saturated solution of 

 picric acid, 100 ; nitric acid, 2). When the tissue is per- 

 fectly flexible so that it may be cut with a scalpel, wash 

 in water until all the acid is removed. Harden in gum 

 and alcohol, section, stain in picro-carmine. 



SALIVARY GLANDS. 

 It is in the guinea-pig or the dog that we may study 

 the serous type (parotid) and the mucous type (sub-max- 

 illary) of mucous glands. 



