254 BUREAU OF ANIMAL INDUcsTllY. 



eye bv pressing the finger and thum)) on the upper and lower lids, so 

 as to cause retraction of the eyeball into the socket. When foreign 

 bodies, such as sand, dust, and chaff, or other irritants have fallen on 

 the eyeball or eyelids, it is similarly projected to push them off', their 

 expulsiqn being further favored by a profuse flow of tears. 



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

 e3'e, and to a very marked degree in lockjavr, when the sj^asm of the 

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

 jects forward the masses of fat and the cartilage. The brutal practice 

 of cutting off this appai*atus, whenever it is projected, necessitates 

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

 ant a most valuable appendage. That tlie cartilage and membrane 

 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 an^' warrant for its removal. It is 

 usually but the evidence of the presence of some pain in another part 

 of the eye, which the suffering animal endeavors to assuage by the use 

 of this beneficent provision. For the diseases of the cartilage itself, 

 see "Encephaloid cancer." 



LACiraTMAL APPAEATUS. 



This consists, firs-t, 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 the eyeball, and the 

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

 there directed bj^ a small conical papilla (lachrymal caruncle) into two 

 minute orifices, 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 part 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 opening is 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 e5'e: The eye, and to a certain extent, 

 the mucous membrane lining the eyelids, may" be exposed to view by 

 gently parting the ej-elids with the thumb and forefinger pressed 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 bj- gentleness and careful graduation of the pressure this 



