4 
While the celloidin shreds are drying pour 25 c.c. absolute alcohol into an absolutely dry, 
wide-mouthed bottle. I use the shell vial, 10 cm. in height and 3 cm. in diameter, supplied 
by the bureau. Be sure that the bottle has a good, tight stopper. Add to the absolute alco- 
hol placed in this bottle an equal volume of ether. Label the bottle ‘‘Absolute alcohol-ether 
mixture.’ Be sure that in measuring out these liquids the graduate used is perfectly dry so 
far as water is concerned. Keep the absolute alcohol-ether mixture tightly Sorte to prevent 
evaporation of be liquid, which is very volatile. 
Add the 24 grams of thoroughly dried celloidin to this absolute ‘Toate ae mixture. 
Let this stent shakane occasionally to hasten the solution—until the celloidin has dissolved 
and the whole has become a homogeneous, thick, sirupy mass. This may require a day,or two. 
Label the bottle ‘‘Thick celloidin.” 
Prepare a thin solution of celloidin as follows: Take another thoroughly dry, wide-mouthed 
bottle, similar to that already used, and pour into it about a third of the solution from the 
first or thick celloidin bottle. Add to this an approximately equal volume of a mixture of 
. equal parts absolute alcohol and ether. Label the bottle “thin celloidin” and keep it tightly 
corked ready for use. . 
During the final stages of preparing the above solutions proceed to dehydrate the object 
to be embedded as follows: 
(a) Assume the object to have been preserved in 70 per cent alcohol. 
(b) Transfer it to 95 per cent alcohol, or, if the object is not easily handled, remove the 
70 per cent alcohol with a pipette and replace it similarly with 95 per cent. The object should 
remain in this for a day as a general rule. 
(c) Transfer the object to absolute alcohol. (In the case of objects not easily handled 
with a forceps, use the pipette as above, but be sure that the pipette used to transfer the abso- 
lute alcohol is perfectly dry.) Allow the object to stay in the absolute alcohol from 8 to 24 
hours, depending on its size and penetrability. 
(i) Transfer the object to a second bath of fresh absolute alcohol. This is to get rid of 
the last trace of any water that might possibly be in the object. Objects will not be satisfac- 
torily infiltrated with the celloidin so long as any water remains in them. Where objects are 
not readily handled modify the transfer as indicated above. . 
(e) After from 8 to 24 hours remove the absolute alcohol with a dry pipette and replace it 
with a mixture of equal parts absolute alcohol and ether like that used in making up the celloidin 
solutions. Let the object stay in this mixture at least one day; it may remain in it indefinitely — 
without harm. 
Next transfer the object to the thin celloidin or else replace the absolute alcohol-ether 
mixture with it, using the precautions indicated above. Be sure that all instruments that 
come in contact with the liquids are perfectly dry. The object must remain in the thin cel- 
loidin for a considerable time, the exact duration of the bath depending on the character of 
the material. With most objects it,is usually advisable to leave them in it a week. 
Transfer the object as before to thick celloidin. It should remain in this about as long 
as in the thin celloidin. 
When there is every reason to believe that the object has been thoroughly infiltrated with 
the celloidin, the next thing to do is to mount it. For this purpose we may proceed as follows: 
(a) Take a water-color mold. Grease the inside of this with vaseline so that the entire 
inner surface is coated with a thin film. Fill the mold about one-fourth full of thick celloidin. 
Remove the object from the celloidin bath and place it in the mold where it will rest on the 
layer of celloidin and where it may be oriented into any desired position. Finally fill the mold 
with thick celloidin. In orienting the object in the celloidin use needles moistened with ether. 
