262 Transactions.— Zoology. 
of mammalian and other skulls, the sternum and sternal ribs of reptiles and 
mammals, and other partly or wholly cartilaginous portions of the skeleton 
of the higher animals. 
The skeleton of Ceratodus was prepared from a specimen which had been 
for a long time in alcohol; when cleaned it was put through the process 
described above, as a whole, the cartiliginous and bony portions being too 
intimately united to allow of the former being prepared alone. This skele- 
ton has now been prepared for upwards of six months, and shows no signs 
of deterioration. During the whole process it only lost J, of its length, 
and even the notochord is hardly more shrunk than in a spirit specimen. 
The trouts’ skulls were prepared by plunging in boiling water for a few 
- seconds, and then removing the membrane bones; the chondrocranium, 
Meckel’s cartilages and the branchial arches only being put through the 
glycerine jelly process. After nearly six months the shrinking of the chon- 
drocranium is so slight that the membrane bones fit into their places with 
almost perfect accuracy. The chief drawback to this preparation is the bad 
colour taken by the cartilage bones, which of course have to be put through 
the preserving process ; they assume much the colour of the cartilage and 
cannot be brought to the same state of whiteness as the membrane bones, 
which are dried at once. 
The same objection applies to such parts of the fetal skeletons, which 
were put through the preserving process entire. In the case of long bones, 
the plan was adopted of macerating until the epiphyses could be easily 
removed, and then preparing these latter alone, and afterwards wiring them 
on to the shafts. After several weeks the shrinking in these is quite 
unnoticeable. 
8. Internal organs. The method has been tried for the hearts of the 
skate, dogfish, and leopard-seal, the stomach and intestine of the skate, 
and brains of the skate and sheep. All such structures are first thoroughly 
hardened in alcohol or chromic acid, and are then subjected to the same 
process as the cartilaginous skeletons, care being taken to support them 
carefully in the desired position while drying: veins, for instance, have 
to be kept open with cylinders of card- board, and so on. It is best to 
make any dissection of these organs after their removal from alcohol, they 
can, however, be trimmed conveniently when thoroughly dry. As 
the thinner organs are more successful than those of considerable thick- 
ness ; the intestine of the skate, for instance, with the spiral valve displayed, 
shows no perceptible shrinking: while the ventricles of the seal’s heart 
are perceptibly thinner than before drying ; none of the details of structure, 
however, being lost. These organs, like the bones, assume a dark colour, 
and are not very attractive as ——- as are, however, — 
