94 
M. CH. MARTIN. 
of eructation, but what remained on the manger was blown after¬ 
wards, and with much force, by the expired air. 
VI. 
Cribbing is a bad habit acquired by horses in the stable, as a 
consequence: 1st. of the bad disposition of the hay-racks and 
mangers; 2d. of the insufficiency of the size of the ration ; 3d. 
of idleness and inactivity. 
To well understand the mode of action of the first of these 
causes, let us look how the prehension of solid food is performed 
by horses. 
Colin in his Physiology says : “ The horse and the other soli- 
peds use their lips and incisives teeth both to take their food 
either at the hay-rack or the grass yet attached to the ground, or the 
oats and the other divided and pulverized substances. Their 
long, very movable and excessively sensible upper lip serves to 
gather the grass and slips of hay, and then the incisors take hold 
of it and pull it from its place.” 
The eminent professor has omitted to tell us how, by what 
motion, this action of pulling is done ; I will try to fill up the 
gap and explain the process. 
When the animal is at grass, the lips and the incisor teeth are 
not always sufficient to tear the grass from the ground, as the teeth 
are not made to cut neatly and at once plants of a fibrous and 
resisting structure. In the same way in the stable, to pull off hay 
from the rack, or straw from the bundle, the action of the lips and 
teeth is not always enough. 
1st. At grass, when the plant is resisting, the action of these 
organs failing, the animal executes a movement of elevation of 
the head. It is this motion from below upwards, produced by 
the levator and extensor muscles of the head, which comes to 
assist the deficient action of the lips and teeth in the prehension 
of the blades of grass. 
The action is so much more evident and marked when the 
grass is tougher; it is scarcely visible when the grass is short and 
tender. It is easily made evident and marked, if a tied bundle of 
clover, secured to the ground, is offered the animal to eat. 
