346 SOME OTHER H1STOLOGIOAL METHODS. 



Bones should be plunged into water as soon as the sur- 

 rounding soft parts have been removed, and should be divided 

 into lengths with a saw whilst wet. The medulla should 

 then be driven out from the central canal by means of a jet 

 of water ; spongy bones should be submitted to hydrotomy. 

 This may be done as follows : An epiphysis having been 

 removed, together with a small portion of the diaphysis, a 

 piece of caoutchouc tubing is fixed by ligature on to the 

 cut end of the diaphysis, and the free end of the piece of 

 tubing adapted to a tap through which water flows under 

 pressure. 



As soon as the bones, whether compact or spongy, have 

 been freed from their medullary substance they are put to 

 macerate. The maceration should be continued for several 

 months, the liquid being changed from time to time. As 

 soon as all the soft parts are perfectly destroyed, the bones 

 may be left to dry. When dry, they should be of an ivory 

 whiteness, and their surfaces exposed by cutting of a uniform 

 dulness. 



Thin sections may then be cut with a saw and prepared by 

 rubbing down with pumice-stone. Compact pumice-stone 

 should be taken and cut in the direction of its fibres. The 

 surface should be moistened with water and the section of 

 bone rubbed down on it with the fingers. When both sides 

 of the sections have been rubbed smooth in this way, another 

 pumice-stone may be taken, the section placed between the 

 two, and the rubbing continued. As soon as the section is 

 thin enough to be almost transparent it is polished by rubbing 

 with water (with the fingers) on a Turkey hone or lithographic 

 stone. Spongy bone should be soaked in gum and dried 

 before rubbing down (but see VON KOCH'S copal process, ante, 

 303, and EHRENBAUM'S colophonium process, 304). 



WEIL (Zeit.f. wiss. Mik., v, 2, 1888, p. 200) gives a process 

 similar to the foregoing, rough sections or portions of bone 

 and teeth being penetrated with chloroform-balsam, which is 

 hardened in an oven, or over a water-bath, and then ground. 



NEALEY (Amer. Hon. Mic. Journ., 1884, p. 142; Journ. Roy. 

 Mic. Soc., 1885, p. 348) says that perfectly fresh 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. 



