BONE, TEETH 427 



Fanz (Anal. Record, xiv, 1918, p. 493) employs sand or carborundum 

 paper of different grades of coarseness for grinding, using the back or 

 smooth side of a piece of sandpaper for polishing the section. He 

 recommends shellac in preference to balsam for attaching the section 

 to the glass slip. 



911. White [Journ. Roy. Mic. Sac, 1891, p. 30T) recommends 

 the following : Sections of osseous or dental tissue should be cut 

 or ground down moderately thin, and soaked in ether for twenty- 

 four hours or more. They should then be put for two or three 

 days into a thin solution of fuchsin in collodion, then into spirit 

 to harden the collodion. After this they are ground down to the 

 requisite thinness between two plates of old ground glass, with 

 water and pumice powder, and mounted, surface dry, in stiff 

 balsam or styrax, care being taken to use as little heat as possible. 

 Lacunae, canaliculi, and dentinal tubuli are found infiltrated by 

 the coloured collodion. 



Hanazawa (Dental Cosmos, lix, 1917, pp. 125 et seq.) gives a number 

 of methods for staining ground and decalcified sections of dentine to 

 demonstrate its minute structure. 



Matschinsky (Arch. mik. Anat., xxxix, 1892, p. 151, and xlvi, 1895, 

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



For similar method of Ruprecht, see Zeit. iviss. Mik., xiii, 1896, p. 21, 

 wherein see also quoted (p. 23) a method of Zimmermann. 



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

 fresh bane to 120 ^ ; and Arndt (Zeit. zviss. Mik., xviii, 1901, p. 146) a 

 double saw which will also give very thin sections. 



912. Mounting. To show lacunae and canaliculi injected with 

 air, take a section, or piece of very thin fiat bone, quite dry. 

 Place on a slide a small lump of solid balsam, and apply just 

 enough heat to melt it. Do the same with a cover-glass, place 

 the bone in the balsam, cover, and cool rapidly. 



When thin ground sections of enamel are mounted in Canada 

 balsam it is found often that they appear almost structureless. 

 To demonstrate the enamel pattern of such sections they may 

 be etched by immersion in 0-6 per cent, of hydrochloric acid in 

 70 per cent, alcohol, or in a weak aqueous solution of picric acid, 

 and mounted in Camsal balsam or Euparal, media which, on 

 account of their low index of refraction, will be found to disclose 

 the structure of the enamel more easily. 



913. Ebner's Method for Bone Fibrillae and Lamellae. The 

 NaCl — HCl method recommended by Ebner is very useful when 

 demonstration of the fibrillae and lamellae of bone tissue is desired. 

 It is also applied for demonstration of the primitive rods. How- 

 ever, this method damages cell structures and nuclear staining. 



Decalcification ; solution ; 100 c.c. of saturated sodium chloride 

 is diluted with 100 c.c. of water and 1 c.c. (for teeth use 10 to 

 20 c.c.) of commercial hydrochloric acid is added. During the 



