SYSTEMATIC SYNTHESIS OF TISSUES INTO ORGANS. 303 



constructed to work together harmoniously for a given 

 common result. 



814. THE TEAR (Lachrymal) APPARATUS is CON- 

 STRUCTED of a gland to form the tear-fluid, ducts to con- 

 duct it to the eye, and ducts to conduct away what does 

 not evaporate. The lids and the Meibomian glands might 

 also be counted as necessary to distribute the fluid over 

 the eye, and also to prevent it from running over the 

 lids. 



815. THE LACHRYMAL GLAND is CONSTRUCTED of two 

 parts (Plate 4), the rounded and the flat, situated just 

 within the socket above the eye, and to the outside of 

 it. The rounded part is about the size of a sparrow's or 

 robin's egg, the flat or thin part being smaller. Six to 

 a dozen minute tubes lead from all parts of the gland, 

 within which an immense number of minute cryptse or 

 pouches surround the tubes, and pour into them the 

 tear-fluid secreted from the blood. The tubes or ducts 

 open at their lower extremity upon the under surface of 

 the upper part of the lid, and pour the fluid into the eye, 

 over which it is spread by the motion of the lids. 



816. THE TISSUES OF THE GLAND are the sinewy in 

 very small quantity, the secretory chiefly, and the nerv- 

 ous. The Blood-tubes of the gland are very large in 

 proportion to its size, though not exceeding a large 

 knitting-needle in diameter: the amount of fluid the 

 gland can secrete in a short time, under strong mental 

 influences, is astonishing. 



Remark. The only creature that weeps is Man. Other creatures 

 have tear-glands for supplying fluid to moisten the eye, and in case of 

 injury it sometimes overflows and trickles down; but the flow of tears 

 proper, under the influence of emotions, is only human. 



817. TWO BLACK POINTS, TO BE SEEN AT THE INNER 



ANGLE OF THE EYE by turning out the lids, are the open- 

 ings of two minute tubes that curve around and connect 



814. How is ? 815. How is ? Place the finger over the opening of tubes 

 from L duct 816. What are ? 817. What arc ? 



