4. What is "moonblindness"? Give the symptoms.

5. Describe the symptoms of infectious ophthalmia of ruminants and the
treatment.




CHAPTER XIII

GENERAL DISEASES OF THE LOCOMOTORY APPARATUS


GENERAL DISCUSSION.--The movements of the different parts of the animal
body depend on the union of the bones that form the skeleton (Fig. 28), and
mode of insertion of the muscles. The bones meet and form _joints_ or
_articulations_. These are divided into three classes: _movable_, _mixed_
and _immovable_. Nearly all of the articulations in the extremities belong
to the movable class. The articulations between the bodies of the vertebrae
belong to the mixed, and those between the flat bones of the head to the
immovable class.

[Illustration: FIG. 28.--Skeleton of horse.]

The bony surfaces that meet and form the different types of articulations
are held together by ligaments (Fig. 29). Sometimes the ligament is placed
between the bony surfaces, but usually it is attached to the margins of the
articular surfaces that it unites. The _immovable class_ possesses
fibrous-like ligaments that are placed between the margins of the flat
bones that form the articulation. The _mixed articulations_ are united by a