THE SPECIAL SENSES 277 



56. The Lachrymal Fluid, or the Tears. Just within the 

 outer part of the bony arch of the brow, where the bone may 

 be felt to be sharper than in other positions, is lodged a little 

 organ called the lachrymal gland, the situation of which is 

 indicated in Fig. 63, 1. This is the gland whence flows the 

 watery secretion, commonly called the tears, which is designed 

 to perform an exceedingly important duty in lubricating the 

 lids, and in keeping the exposed surface of the eyeball moist 

 and transparent. For, without this or some similar liquid, the 

 front of the eye would speedily become dry and lustreless, like 

 that of a fish which has been removed from the water; the 

 simple exposure of the eye to the air would then suffice to 

 destroy vision. 



57. This secretion of the tears takes place at all times, 

 during the night as well as the day ; but it is seldom noticed, 

 unless when under the influence of some strong mental emo- 

 tion whether of sorrow or happiness it is poured forth 

 in excess, so as to overflow the lids. Strong light or a rapid 

 breeze will, among many other causes, excite the flow of the 

 tears. That portion of this secretion which is not used in 

 moistening the eye is carried off into the nose by a canal situ- 

 down with the eyes closed. Taking hold of the lashes with one hand, 

 and applying a pencil, or some small, round, smooth object, over the lid 

 above the globe, we lift the lashes out and up, warning the person to still 

 keep looking down. The lid will suddenly turn over with a little spring 

 from the bending of the cartilage. In this way nearly the whole of the 

 conjunctival sac will be exposed, and any foreign body wiped away, as 

 above described. But suppose no friend or oculist is by us to do this. 

 The next best thing is to take hold of the lashes of the upper lid, and 

 draw it forward and downward over the lower one, blowing the nose 

 violently with the other hand at the same time. 



" If the foreign substance is on the cornea, take a strip of paper not 

 stiffer than ordinary writing-paper, about a quarter of an inch wide, and 

 roll it up as if you were going to make a candle-lighter. Look at the 

 lower end, and you will see it comes to a point. With this point now you 

 may safely attempt to remove any foreign substance from the cornea. 

 The tears which will flow soften the paper, and prevent injury to the 

 delicate covering membrane of the cornea." Dr. B. Jay Jeffries. 



56. The location of the lachrymal gland ? The use of the gland ? 



57. When does the secretion of the tears occur ? The secretion not used for the eye ? 

 Location of the nasal duct ? Its use ? The overflow of tears in old people ? 



