J A 
10 
Figs. 15 and 16 represent a penknife and scalpel with elongated 
blades or shafts, to admit of their being introduced into the egg to cut 
up the embryo. Fig. 15 is also, perhaps, the best instrument with 
which to remove the lining membrane from the hole. This is done 
by inserting the blade perpendicularly, and slightly scraping the edge 
of the hole as soon as it is drilled. 
Fig. 17 represents a forceps for extracting the pieces of the embryo 
when cut up. The spring should not be too lively, as its resiliency 
may occasion breakage. The grasping surfaces should be roughened 
to prevent the pieces slipping.* 
§ V. 
PREPARATION OF SPECIMENS. 
Eggs are emptied with the least amount ot tiouble at one hole,!’ 
which should be made at the side of the specimens, as shown in the 
annexed engravings (figs. 18 and 19), with one of the drills already 
described (figs. 1,2, 3). The hole should of course be proportioned to the 
size of the egg and the amount of incubation it has undergone. Eggs 
that are hard sat upon are more easily blown by being kept a few days, 
but the operation must not be deferred too long or they are apt to 
burst violently immediately on being punctured, though this may be 
avoided by holding them under water while the first incision is made. 
The hole being drilled, the lining membrane should be cleared away 
* Most, if not all, of the implements here described may be obtained of any 
surgical-instrument maker. I have pleasure in mentioning the name of Mr. J. Evrard, 
of 35, Charles Street, Middlesex Hospital, as that of the workman who for some years 
past has supplied several of my friends and myself. He fits up neat and convenient 
pocket-cases with a set of all the most useful tools for egg-blowing and bird-skinning. 
Mr. David Mackenzie,of 58, South Bridge, Edinburgh, I have been informed, furnishes 
drills, blow-pipes, &c., and at a most reasonable rate. I believe that the Smithsonian 
Institution of Washington will, with its usual liberality, equip any of its correspondents 
in America according to their requirements. 
f Those who may still prefer to blow eggs by means of 
two holes are particularly requested not to make them at 
the ends of the eggs, nor at opposite sides, but on the same 
side (fig. 20). In this case the hole nearest the smaller 
end of the egg should be the smallest, and the contents 
blown out at the other. If the holes are made at the ends 
of the eggs it not only very much injures their appearance 
as cabinet specimens, but also prevents their exact dimen¬ 
sions from being ascertained accurately; and if they are made at opposite sides the 
extent of the “ show surface ” is thereby lessened. 
Fig. 20. 
