1889.] Microscopy. 521 
pieces, "allowing water to trickle over it the while." The 
pieces are then laid in concentrated sublimate solution for 
some time to fix the soft parts. After this they are washed in 
running water for about one hour, then placed in 30 per cent, 
spirit, which in twelve hours is changed to 50 per cent., again, 
after a similar period, to 70 per cent. Then, in order to re- 
move the black sublimate precipitate, the teeth are laid for 
twelve hours in 90 per cent, spirit, to which 1.520 per cent, 
tincture of iodine has been added. The iodine is afterward re- 
moved by immersion in absolute alcohol until the teeth be- 
Forstaining, alcohol, or an aqueous solution of borax carmine, 
gave the best results. From the absolute alcohol the teeth are 
removed to running water from fifteen to thirty minutes, and 
then placed in the stain. In the aqueous solution of borax 
carmine they remain one or two, in the alcoholic two or three 
days. They are then transferred to acidulated 70 per cent, 
alcohol (alcohol 100 ccm., acid, muriat, i.o) in which 
they remain, the aqueous ones stained at least twelve, the 
alcohol- stained ones twenty- four to thirty-six hours. This 
done they are immersed for about fifteen minutes in 90 per 
cent, alcohol, and then for half an hour in absolutealcohol, after 
which they are transferred to some etherial oil for twelve or 
more hours. 
The oil is then cjuickly washed off the objects with 
pure xylol, and then 'they are placed for at least twenty-four 
hours in pure chloroform. After this they are passed into a 
solution of balsam in chloroform. The balsam is prepared by 
drying in a water bath, heated gradually up to 90", for eight 
hours or more, until when cold the mass will crack like glass 
on being punctured. Of this balsam so much is added to the 
chloroform as to make a thin solution in which, as before 
mentioned, the teeth lie for twenty-four hours. After this 
time as much balsam is added to the solution as will dissolve. 
When no more balsam will dissolve, the teeth and a sufficiency 
of the balsam are poured into a vessel and heated up to 90^ in 
a water bath, until the mass when cold should be as hard as 
glass. When the balsam is sufficiently set the teeth are care- 
fully picked out, placed in a vice, and their discs are cut from 
them with a fret saw. water being allowed to trickle over them 
the while, and then they are ground in the usual way. Ihe 
preparations are mounted in chloroform balsam. 
