THE EYE. 



closely adherent to the back of the upper eyelid, and is covered on the ocular 

 surface merely by the conjunctiva ; its lobules are small and separate, with minute 

 ducts, some opening separately, others joining the ducts from the principal gland, 

 which are also very small. The number from both divisions of the gland seldom 

 exceeds twelve. After running obliquely under the mucous membrane, and 

 separating at the same time from each other, they open in a row at the fornix con- 

 junctivae, by separate orifices, at its upper outer part. 



Structure. The lachrymal gland is a compound tubulo-racemose gland 

 resembling the serous salivary glands in general structure. Its alveoli are bounded 



Fig. 8. ALVEOLI OF THE LACHKYMAL GLAND OF THE DOG : A, FROM A GLAND IN THE RESTING 



STATE ; B, FROM ANOTHER GLAND WHICH HAD BEEN SECRETING FOR THREE HOURS PREVIOUSLY. 



(E. A. S.) Highly magnified. 



The glands were hardened in chromic and osmic solution. In A the cells are filled with the 

 materials of secretion ; in B, these are mostly discharged, and the cells are shrunken and vacuolated. 



by a basement membrane formed of ramified flattened cells ; and the secreting cells 

 exhibit changes in the different states of rest and activity of the gland similar to 



Fig. 9. FRONT OF THE LEFT EYELIDS WITH THE LACHRY- 

 MAL CANALS AND NASAL DUCT EXPOSED. 



1,1, upper and lower lachrymal canals, showing towards 

 the eyelids the narrow 1 ent portions and the puncta lacri- 

 raalia ; 2, lachrymal sac ; 3, the lower part of the nasal 

 duct ; 4, plica semilunaris ; 5, caruncula lacrimalis. 



those seen in most other glands (see fig. 8 and 

 Vol. I., Part 2, p. 396). No rod-like structure has 

 been noticed in the epithelium of the ducts. The 

 arteries of the gland are derived from the lachry- 

 mal, and the veins pass into the ophthalmic vein. 

 The nerves come from the lachrymal branch of 

 the ophthalmic and from the sympathetic. 



Lachrymal canals. These commence as 

 already mentioned by a minute aperture (punc- 



tiun) on the margin of each lid, near the inner angle (figs. 9, 10 and 11). The 

 upper punctum is slightly smaller and is situated rather more mesially than the 

 lower one. The upper canal is rather the smaller and longer of the two ; it 

 first ascends for 2 mm. from the punctum ; then makes a sudden bend, and 



