177 
Several small skulls may be boiled at the same time if adult and 
young specimens are not mixed up. The juvenile specimens will not stand 
much boiling without falling to pieces. Put each skull in a small, cylin- 
drical glass vial with label (number) written with pencil on a piece of 
tough paper or stencilled on pure tin, aluminium, or Monel metal. Put 
enough water in the vials to cover the skulls, plug the vials with a bunch 
of cotton, set in a saucepan, and boil as long as necessary. The heat is 
easier to regulate if a gas-burner is used. 
The usual method of mending broken bones is by using a good brand 
of liquid glue or celluloid dissolved in acetone. The writer has recently 
examined some small skulls mended by Mr. J. Dewey Soper, using liquid 
solder in tubes. He finds that if there is no objection to the silvery colour, 
which is barely noticeable if the joint is neatly made, the solder dries 
rapidly and offers rapid control and manipulation. The solder is especially 
useful in uniting the members of separated lower mandibles. Treat the 
edges of both parts with the solder, bring into contact, and almost immedi- 
ately the specimen may be laid aside without further holding, and the 
parts are there to stay. 
Holden’s Method of Cleaning Skulls. Holden’s method (1914, 1917) 
of cleaning skulls by stewing in a solution of crescylic acid (C 3 H 4 CH 4 
OH), ammonia, and water was formerly used in the National Museum of 
Canada, but has been discarded on account of the difficulty of keeping 
the strength and time of boiling exactly right for specimens of different 
ages 
Rowley’s Method of Cleaning Skulls and Bones. As boiling has a 
tendency to crack and loosen teeth, Rowley (1925, 214) recommends that 
skulls be treated separately in the same manner as ligamentary skele- 
tons. The solution used is water, 1 gallon; pancreatin, 2 heaping 
tablespoonfuls; sodium sulphide, one tablespoonful. The pancreatin acts 
as a digester in softening flesh. Too much heat is bad; a low, even tem- 
perature accompanied by motion in the solution is best, and may be 
obtained by a steam pipe playing into the solution. A simple apparatus 
may be made from a gallon oil can. Solder a crossbar to the screw cap 
so it is easily detachable. Solder a nipple over a small hole on the 
other side of the top and attach a piece of flexible gas-stove hose or 
tubing to the nipple. Fill the can three-quarters full of water and set 
it on a gas plate. When the water boils and the steam comes out of the 
end of the tubing, lower the gas jet until it just keeps the water boiling, 
and stick the end of the tubing into the receptacle holding the solution 
and the bones. A glass preserve jar is good for small specimens, and the 
temperature of the solution will rise to 208 degrees F. in a quart jar. An 
open, white-enamelled bowl about 8 inches across, with the same amount 
of steam, will keep the solution at about 180 degrees F., a good tempera- 
ture in which to work small skulls and skeletons. Small stone crocks are 
cheap and excellent for this purpose. A string may be tied to each speci- 
men so that it may be lifted out from time to time and examined. As 
the steam condenses in the solution the liquid may be dipped out of the 
vessel, and if necessary more sulphide added to compensate for the dilu- 
tion. When clean, the bones are placed in warm water for a short time, 
and then dried, degreased, and bleached. If the bones are not as white as 
desired, they may again be degreased and bleached. 
