4 a eee Pa 8 ot 
\ ‘ ag t 5 
48 THE MICROSCOPE. 
The solution should be changed frequently and specimens 
remain in it for several weeks, or until the bone has become thor- 
oughly softened through removal of the lime salts with which it is 
impregnated. The action of the fluid can be hastened by the addi- 
tion of more acid, but the specimens are much more satisfactory 
when decalcification has been slowly performed. Sections should be 
dipped in an aqueous solution of picric acid, then stained with car- 
mine and mounted in glycerin. 
As was said in the beginning, both of the above-given 
methods for preparing bone sections are unsatisfactory. 
By the first method the soft parts are entirely destroyed, 
and by the second much altered. Nor do the hard parts remain 
unchanged. No method will give perfect results; but first infiltrating 
the bone with Canada balsam or some such substance, which will 
“set” well and thus hold the parts of the tissue together whilst 
being prepared, is the only method which will preserve the soft 
parts in a tolerably unchanged state and prevent any marked altera- 
tion in the harder portions. 
A good, though rather tedious method for performing this infil- 
‘tration has been proposed by Dr. Weil, in a late number of the Zeitsch. 
f. Wiss. Mik. (Bd. V., S. 200.), which is as follows: 
The bone must be fresh and cut with a fine saw into the thinnest 
possible sections. These are to be placed for a few hours in a concen- 
trated sublimate solution, in order to fix the soft parts. After washing 
thoroughly in water put them into 30 per cent. alcohol; then, after 
at least 12 hours, in 50 per cent. alcohol, and then, after a like time, 
in 75 per cent. alcohol. In order to remove the black, sublimate 
precipitate, they are placed for another 12 hours in 90 per cent. 
alcohol, to every 100 cc. of which 1.5 to 2. tincture of iodine has 
been added, ‘The iodine is removed by placing the sections in abso- 
_ lute alcohol, where they are left for some time until they become 
_ whitened. 
They should now be stained with borax-carmine, which, with an 
aqueous solution, will take from 1 to 2 days, with an alcoholic solu- 
tion, from 2 to 3 days, after which they can be transferred to 70 per 
cent. alcohol, to which 1 per cent. hydrochloric acid has been added, 
where those stained in the aqueous solution remain for at least 12 
hours, and those which have been treated with the alcoholic stain for 
24-36 hours. They are now to be dipped into 90 per cent. alcohol 
and then placed for an hour in absolute alcohol, and finally trans- 
- ferred to some etherial oil for 12 hours or more. 
The oil is now to be removed by washing them in pure xylol, 
