198 Trans. Acad. Sci. of St. Louis. 



and of an inner layer of cylindrical cells. I have never seen 

 ciliated cells (Figs. 59, 61). 



The material of lacrymal sacs which I have been able to 

 obtain for microscopical study has been rather limited and I 

 have seldom had an entire lacrymal sac for examination. 

 Usually it was only the upper and temporal part. I there- 

 fore cannot give from my own knowledge a more detailed 

 description of its structure and will refer only to one point of 

 interest, which, more especially, belongs to this paper, deal- 

 ing, as it is, with the glandular organs belonging to the eye- 

 ball and its appendages. 



It has been, and still is, a moot question, whether or not 

 true glandular tissue is found in the walls of the lacrymal 

 sac. From my specimens I cannot see how the existence of 

 such glandular tissue can be doubted. As to the character of 

 the glands and their secretion we can only speculate by com- 

 parison with other glands. I find usually two forms of glands 

 and both of these often in considerable numbers, especially in 

 the wall opposite the entrance of the collecting tube of the 

 canaliculi. 



The one kind is of the acinous type and corresponds in its 

 structure exactly with the acinous glands found in the eye- 

 lids, conjunctiva and caruncle (Figs. 62 to 66). The struc- 

 ture of the other kind is more that of tubular glands, like the 

 sudoriferous glands (Figs. 67, 68.) 



I have never had an occasion to examine the structure of 

 the nasal lacrymal duct. 



REMARKS ON THE LITERATURE CONCERNING THE SUBJECTS OF 



THIS PAPER. 



In how far, what I have found and described in the forego- 

 ing pages corresponds with or disagrees with what other 

 investigators on this subject have found and laid down in 

 literature, may be judged from the following brief survey of 

 the more important works on the subject from the literature 

 at my disposal. 



I started out more particularly on this investigation, because 

 I could get no satisfactory explanation as to what glands 

 were referred to by the different authors, when speaking of 



