13 
chick can be got out with the help of a hook, scissors, blowpipe, 
and plenty of water; but the operation takes time. In cases of 
emergency, and when time is of importance, a neat oval piece of 
shell can be cut out with a sharp pair of curved dissecting scissors ; 
the chick can then be cut up in the shell and extracted without 
trouble. When the shell has been thoroughly cleaned inside, the 
oval piece can be neatly replaced and fixed with collodion or fine glue. 
If it is very important not to damage the shell, other and more 
tedious means have to be resorted to. A fairly large hole is bored, 
and when as much of the contents of the egg as possible have been 
blown out—that is, all yolk and albumen—a drop or two of saturated 
solution of Caustic Potash should be introduced with the aid of a 
glass suction-pipe. It is most important that all yolk and albumen 
be removed before using the solution, as the Potash turns the former 
into an indiarubber-like mass which cannot afterwards be removed, 
and the latter into a hard glass-like substance. The solution should 
be left in the ege for about twenty minutes, and when washed out, 
a portion of the embryo will come with it in a softened state. This 
operation may have to be repeated several times. The Potash should 
not be left in the egg longer than is absolutely necessary, or it will 
destroy the shell. Caustic Potash should be used with great care, 
and kept carefully from the fingers and mouth, and the bottle in 
which it is kept should be very strong and securely stoppered. With 
very delicate eggs in an incubated condition, it is sometimes safest to 
fill the shell with water and let the chick gradually rot ; but this 
is a slow and disagreeable process, and not always possible to carry 
out when one is collecting in the field. The delicate inner lining 
of the egg-shell enveloping the embryo, known as the Allantois, 
must be removed, or the shell will decay. This can usually be 
done by sucking up water into the mouth and blowing it into the 
shell through the blowpipe; but if the membrane cannot be 
extracted in this way, a piece of string or cotton according to 
the size of the egg should be inserted and twisted about. The 
lining membrane usually sticks to the cotton and can then be 
withdrawn. 
When neither drill nor blowpipe is available, eggs can easily be 
blown through two holes, bored one near each end by some sharp 
instrument such as a pin or sharp thorn, the latter being often quite 
a useful substitute for a drill. 
