CONNECTIVE TISSUES. 355 



powdei', and mounted, surface dry, in stiff balsam or styrax, 

 care being taken to use as little heat as possible. Lacuna, 

 canaliculi, and dentinal tubuli are found infiltrated by the 

 coloured collodion. 



Matschinsky {Arch. mih. Anat., xxxix, 1892, p. 151, and xlvi, 1895, 

 p. 290), after grinding, impregnates witli nitrate of silver. 



For similar method of Rupeecht, see Zeit wiss. Mih., xiii, 1896, p. 

 21, wherein see also quoted (p. 23) a method of Zimmbemann. 



CsoKOK (Verh. anat. Ges., 1892, p. 270) describes a saw which will cut 

 fresh bone to 120 /* ; and Arndt {Zeit. wiss. Mik., xviii, 1901, p. 146) a 

 double saw which will also give very thin sections. 



711. Mounting'. — To show lacunae and canaliculi injected 

 with air, take a section, or piece of very thin flat bone, quite 

 dry. Piace on a slide a small lump of solid balsam, and 

 apply just enough heat to melt it. Do the same viii\\ a 

 cover glass, place the bone in the balsam, cover, and cool 

 rapidly. 



712. Sections of Bones or Teeth showing the Soft Parts. — 



Nealey [Amer. Mon. Mic. Juurn., 1884, p. 142 ; Journ. Roy. 

 Mic. Sor., 1885, p. 348) says that perfectly /res^ portions of 

 bone or teeth may be ground with emery on a dentist's lathe, 

 and good sections, with the soft parts in situ, obtained in 

 half an hour. 



Hopewell-Smith (Journ. Brit. Dent. Ass., xi, 1890, p. 310; 

 Journ. Roy. Mic. Soc, 1890, p. 529) says that for preparing 

 sections of teeth showing odontoblasts in situ the best plan 

 is to take embryonic tissues. A lower jaw of an embryonic 

 kitten or pup may be taken, and hardened in solution of 

 Miiller followed by alcohol, then cut with a freezing micro- 

 tome. 



Weil [loc. cit., § 180) fixes pieces of fresh teeth in subli- 

 mate, stains with borax-carmine, brings them through alcohol 

 into chloroform and chloroform-balsam, and after hardening 

 this by heat proceeds to grind as usual (§ 177). 



See also Eosb, § 710. 



For the study of the vessels in teeth, Lepkowsky [Anat. 

 Hefte, viii, 1897, p. 568) injects with Berlin blue, hardens 

 the teeth with a piece of the jaw for one or two days in 50 

 per cent, formol, decalcifies in 10 per cent, nitric acid (eight 



