120 



ANIMAL MECHANISM. 



FIG. 10. 



through a bony tube, answering the double purpose of 

 softening and keeping moist the living membrane, on 

 which the sense of smell depends. On both eye-lids, 

 at the roots of the eye-lashes, are in each, a row of glands, 

 equivalent to bags, smaller than pin heads, which ooze 

 out an oily secretion, to prevent the adhesion of them to- 

 gether, as is sometimes the case when the eyes , are 

 much inflamed. Surely such manifest provision for 

 contingencies, and for the preservation of this one 

 piece of mechanism, indicates Super-human contrivance. 

 Explanation of Figure 10. 



This plan exhibits the na- 

 tural size of the passages of 

 the t<ears. 

 a Is the lacrymal gland, or 



in other words, the organ 



that secretes the tears; 



showing its natural situa- 



tion, with respect to the 



eye-lids. 

 bb The eye-lids, widely 



opened. 

 c The situation of the 



puncta lacrymalia, or the 



holes, at the inner angles 



of the lids, through which 



the tears flow, to get into 



the tube which finally con- 



veys the fluid to the nose. 



dd The ducts continued from the puncta lacrymalia. 

 ee The angles which the ducts form after leaving the puncta. 

 / The termination of the lacrymal ducts in gg. 



fg The lacrymal sac. 

 The nasal duct, continued from the lacrymal sac. 



ON SEEING AT A DISTANCE. 



When we speak of the distance to which vision extends, 

 we can understand either the sphere of distinct vision, or 

 of seeing in general. The latter has a much larger 

 semi-diameter than the former ; and the series for the one 

 is in animals different from that of the other. The extent 

 of distinct vision, is pretty nearly in relation with the 

 distance of the lens from the retina in the axis of the eye. 

 But the power of seeing at a distance, depends, in gene- 



