ANIMAL MECHANISM. 101 



which all the brute creation have the sagacity to under- 

 stand. When one of the four straight muscles is shorter 

 than its fellow on the opposite side, it produces the cross- 

 eye, or squinting. 



FIG. 1. 



Explanation of Figure 1. 



This plan, from a careful dissection of the right eye, exhibits the 

 muscles, viewed obliquely from its upper and outer side. 

 a The eye-ball. 

 5 Part of the upper eye-lid, 

 c Tunica Conjunctiva, or inclination of the common skin of the 



forehead, which turns over the edges of the lids, anil is finally 



carried over the front of the globe, but is perfectly transparent 



at this point. 



d The integuments of the right side of the nose. 

 ee The optic nerve. 

 / The four straight muscles, with the levator, or raising muscle 



of the upper eye-lid, together with the superior oblique muscle, 



embracing the optic nerve where it enters the orbit. 

 g The levator of the lid drawn aside. 



VOL. i. NO. v. 9* 



