PRACTICAL DIRECTIONS. 431 
separate the bones at the sutures. The bones may then usually be 
separated completely by hand. 
Entire skulls, and longitudinal sections, as represented in Fig. 
43, p. 60, should be at hand. 
Study of the Bones.—The bones should be studied in the order in 
which they are described. No further special directions for their 
study are necessary. 
Study of Ligaments.—It will usually not be practicable for each 
student to make the dissections and preparations necessary for study- 
ing the ligaments. Rather should these be examined on demonstra- 
tion preparations preserved in the laboratory. Such preparations 
may most easily be made by using fresh material, and dissecting 
away muscles and other tissues, leaving only the ligaments connect- 
ing the bones. The preparations are then preserved in one or two 
per cent. formalin. It is difficult to prepare the ligaments satisfac- 
torily on preserved material, because they do not stand out clearly 
from other tissues in such material, so that they are not easily dis- 
tinguishable. 
MUSCLES. 
Preparation and Preservation of Matertal.—Formalin forms by far 
the most satisfactory preservative for anatomical material. It is much 
better in almost every respect than alcohol, and has the additional 
advantage of being much cheaper. 
After injecting with formalin, the cat may be preserved either 
immersed in a weaker solution of the same substance, or may be 
kept for a long time simply wrapped in a cloth dampened with 
formalin. The details of preparation differ according to which 
method is to be used. 
In either case, the cat should be killed with chloroform, by 
placing it in a tight jar or box with a cloth or bit of cotton saturated 
with chloroform. It is not necessary to bleed the specimen. When 
the cat is dead, remove it to a tray, place it on its back, and tie the 
limbs loosely so that they will remain outspread. 
Expose the femoral artery in the thigh, as follows: Make a 
median longitudinal incision through the skin of the abdomen, from 
a point an inch or two caudad of the xiphoid process to the pubis. 
Make an incision passing from near the middle of this obliquely 
laterad onto the thigh, for about three inches. Reflect the two flaps 
in the angles between these cuts, then with forceps and tracer isolate 
the femoral artery just as it passes into the thigh (Fig. 127, a). 
Make with scissors an oblique incision in one side of the artery, one- 
half to one inch from the point where it leaves the abdominal cavity. 
Introduce a canula directed toward the body, and tie it in place, 
1. If the cat is to be preserved immersed in a solution of 
formalin, it should now be injected with a five per cent. solution of 
commercial formalin in ordinary water (commercial formalin 5 parts; 
