100 Veterinary Elements. 



(eyelashes) and glands. The eyelashes are to prevent 

 the entrance of particles of dirt, the gland's secretion 

 retains the tears, in sick animals the secretion of these 

 glands is seen at the inner corner of the eyes as a sticky 

 matter. 



The haw, or membrana nictitans is placed at the inner 

 corner of the eye, il; is somewhat gristly in its nature 

 and has the important function of removing dirt from 

 the eye. Its development depends on the use of other 

 members of the body to remove dirt, etc., e. g., in cat- 

 tle it is quite large, whereas in man and monkeys it is 

 very small, the latter being able to remove foreign matter 

 by their hands; its functions being known, none but ignor- 

 ant persons will remove it unless diseased. In lock-jaw 

 (tetanus) it may be seen to be rapidly passed over the 

 eye, if the head is raised or the animal excited, in 

 such cases it aids in the detection of this serious trouble. 



The tear machinery consists of (1) a gland which secretes 

 the tears, situated at the upper part of the eye, (2) a 

 little round reddish brown body in the inner corner of 

 the eye, which directs the tears to (3) the ducts, which 

 carry those tears to the nasal cavity (q. v.). Tears in 

 animals are for the purpose of moistening the eye ball 

 and to wash off small particles of dirt, it is doubtful if 

 they are at all the result of the emotions as in the human, 

 properly speaking "tears" are an accumulation of the 

 secretion of the lachrymal glands, and as such, although 

 the term has been applied to the secretion, cannot be 

 said to exist normally in the animal. The conjunctiva 

 may be considered as a continuation of the skin, joining 

 the eyelids and eyeball, it is very vascular, containing a 



