574 General Notes. [May, 
mine the plane of section. In order to fix the egg in any given 
position in the imbedding mass, Hertwig proceeds as follows: 
a. Asmall block of the hardened mass is washed in water to 
remove the alcohol, and in the upper surface of the block, which 
has been freed from water by the aid of filtering paper, a small 
hollow is made. This hollow is then wet with the freshly pre- 
pared fluid mass. 
6. The egg is washed in water to remove the alcohol, placed 
on a piece of filtering paper to get rid of the water, turned on 
the paper by a fine hair brush until it has the position desired; 
the point of the brush is next moistened and pressed gently on 
the upper surface of the egg, the egg adheres to the brush and 
may thus be transported to the hollow prepared for it in the 
block. i 
c. After the egg has thus been placed in position, a drop of 
absolute alcohol carefully applied will coagulate the “ fluid mass 
with which the hollow was wet, and thus fix the egg to the block. 
The block is again washed, and finally imbedded in the egg-mass, 
which is prepared in the following manner: ; 
Calberla’s Method of Imbedding—The white of several eggs Is 
separated from the yelk, freed from the chalaze, cut with pas 
and thoroughly mixed by shaking with a ten per cent solution 
carbonate of sodium (fifteen parts of the white to one part of the 
solution). The yelk is next added and the mixture shaken T 
orously. After removing the foam and floating pieces of a 
by the aid of filtering paper, the so-called “egg-mass 1S meg 
for use. It is this fluid with which the hollow in the solid bl 
is wet, as before mentioned, the block itself being only a piece 
the same mixture after it has been hardened in alcohol. hite 
Calberla soaks the eggs a few minutes (5-20) in the fresh pen 
of the egg before imbedding ; Hertwig appears to omit this 
of the process. dicated 
After the egg has been fixed to the block as before ek te 
(c), it is placed in a paper box and covered with the fresh 4 
(1-2 deep). The box is then placed in a vessel that rs et 
alcohol (75-80 per cent), enough to bathe its lower me 30-40 
Sel, covered with a funnel, is heated over a water bath or 
minutes, care being taken not to doi/ the alcohol. The aa (ninety 
substance, thus hardened, is next placed in cold alco o a 
per cent), which should be changed once or twice 
twenty-four hours. After remaining in alcohol for al 
eight hours the imbedded egg is ready for cutting. 
1 Morphologisches Jahrbuch, 11, p. 445, 1876 
