THE LACHRYMAL GLAND 1(53 



The methods used for the study of the duct system have been 

 as follows: (1) injection methods, (2) vital staining with pyronin, 

 and (3) histological study of sections. 



The injcclion-corroaion specimens of the duct system ns prepared in 

 this laboratory (Technique II, 2) 



The main duct follows a more or less tortuous course 

 through the palpebral fascia and enters into the gland substance 

 at the outer margin. At this point it is seen to branch. The 

 branching is somewhat variable — generally two different types 

 are seen: (a) a dichotomous branching wherein the main duct 

 divides into two ducts, which by the same method immediately 

 form four ducts, etc. (This method of branching is described 

 for the submaxillary glands by FHnt) and (b) the main duct 

 may continue for some distance into the gland substance 

 somewhat similar to the trunk of a poplar tree, while the primary 

 ducts take origin from this main trunk at various levels. In both 

 instances, however, before the primary ducts take origin, sev- 

 eral small branches are seen to leave the main duct at right 

 angles. These are the ducts of small accessory lobules located 

 on the outer or lateral margin of the gland. 



The primary ducts vary in length, depending upon their 

 distribution. They divide, as a rule, dichotomously into either 

 equal or unequal branches. In the former case, where the 

 branches are equal, these immediately undergo dichotomous 

 branching again to form the interlobular ducts. Where the 

 branches are unequal, the smaller one may directly form an 

 interlobular duct, while the larger one may continue as a pri- 

 mary duct for some distance farther and then branch to form 

 interlobular ducts. Frequently very small branches take origin 

 directly from the primary ducts at right angles as in the case of 

 the main ducts. . These small branches are intralobular ducts 

 which empty directly into the primary ducts from neighboring 

 lobules. 



An extensive ramification of the interlobular ducts is seen. 

 The branching is much similar to that described for the primary 



THE AMERICAN JOURNAL OF ANATOMT, VOL. 20, NO. 2 



