[Fig. 75]


Fig. 75—Model for demonstrating the abdomen and its contents.


*Dissection of the Abdomen.* (Optional)—For individual study, or for a
small class, a half-grown cat is perhaps the best available material. It
should be killed with chloroform, and then stretched, back downward, on a
board, the feet being secured to hold it in place.

The teacher should make a preliminary examination of the abdomen to see
that it is in a fit condition for class study. If the bladder is
unnaturally distended, its contents may be forced out by slight pressure.
The following materials will be needed during the dissection, and should
be kept near at hand: a sharp knife with a good point, a pair of heavy
scissors, a vessel of water, some cotton or a damp sponge, and some fine
cord. During the dissection the specimen should be kept as clean as
possible, and any escaping blood should be mopped up with the cotton or
the sponge. The dissection is best carried out by observing the following
order:

1. Cut through the abdominal wall in the center of the triangular space
where the ribs converge. From here cut a slit downward to the lower
portion of the abdomen, and sideward as far as convenient. Tack the
loosened abdominal walls to the board, and proceed to study the exposed
parts. Observe the muscles in the abdominal walls, and the fold of the
_peritoneum_ which forms an apron-like covering over the intestines.

2. Observe the position of the stomach, liver, spleen, and intestines, and