258 



This protrusion of the cartilage, so as to cover the e3'e, maybe induced 

 in the healthy eye by pressing the finger and thumb on the uj^per and 

 lower lids, so as to cause retraction of the eyeball into its socket- 

 AVhen foreign bodies, such as sand, dust, and chaff, or other irritants 

 have fallen on the eyeball or eyelids, it is similarly projected to j)ush 

 them off, their expulsion being further favored by a profuse flow of 

 tears. 



This is seen, to a lesser extent, in all painful inflammations of the 

 eye, and to a very marked degree in lockjaw, Avhen the spasm of 

 the muscles of the eyeball draws the latter deeply into the orbit and 

 projects forward the masses of fat and the cartilage. The brutal 

 practice of cutting off this apparatus, whenever it is i^rojected, necessi- 

 tates this explanation which, it is hoped, may save to many a faithful 

 servant a most valuable appendage. That the cartilage and mem- 

 brane may become the seat of disease is undeniable, but so long as its 

 edge is thin and even, and its surface smooth and regular, the mere 

 fact of its projection over a portion or the whole of the eyeball is no 

 evidence of disease in its substance, nor any warrant for its removal. 

 It is usually but the evidence of the presence of some pain in another 

 part of the eye, wdiich the suffering animal endeavors to assuage by 

 the use of this beneficent provision. For the diseases of the cartilage 

 itself see "Encephaloid Cancer." 



LACHRYMAL APPARATUS. 



This consists, first, of a gland for the secretion of the tears, and, 

 second, of a series of canals for the conveyance of the superfluous 

 tears into the cavity of the nose. 



The gland is situated above the outer part of tMfe eyeball, and the 

 tears which have flowed over the eye and reached the inner angle are 

 there directed by a small conical papilla (lachrymal caruncle) into 

 two minute orifleos, and thence by two ducts (lachrymal) to a small 

 pouch (lachrymal, sac) from which a canal leads through the bones 

 of the face into the nose. This opens in the lower jjart of the nose 

 on the floor of the passage, and a little outside the line of union of 

 the skin which lines the false nostril with the mucous membrane of the 

 nose. In the ass and mule this oijeningis situated on the roof instead 

 of the floor of the nose, but still close to the external opening. 



EXAMINATION OF THE EYE. 



To avoid unnecessary repetition the following general directions are 

 given for the examination of the eye: The eye, and to a certain extent 

 the miu'ous membrane lining the ej^elids, may be exj)Osed to view by 

 gently parting the eyelids with the thumb and forefinger j)ressed on 

 the middle of the respective lids. The pressure, it is true, causes the 

 protrusion of the haw over a portion of the lower and inner part of 

 the eye, but by gentleness and careful graduation of the pressure this 



