40 SURGICAL APPLIED ANATOMY. [Chap. iv. 



the cervical sympathetic. The recession of the globe 

 is supposed by some to be due to paralysis of the 

 orbitalis muscle of H. Mtiller. This muscle bridges 

 over the spheno-maxillary fissure, is composed of 

 unstriated fibres, and is innervated by the sympathetic. 

 Contraction of the muscle (as produced by irritation 

 of the cervical sympathetic in animals) causes pro- 

 trusion of the globe, while section of the sympathetic 

 in the neck produces retraction of the eye-ball (01. 

 Bernard). No changes are observed in the calibre 

 of the blood-vessels of the globe. 



The globe ; the cornea. The thickness of the 

 cornea varies from -% to -i- of an inch. One is 

 apt to be a little deceived as to its thickness, 

 and on introducing a knife into the cornea, the 

 instrument, if not entered at the proper angle, may 

 be thrust for some little distance among the laminae 

 of the part. In front the cornea is covered by 

 stratified epithelium. When this layer has been 

 removed by abrasion, a white deposit of lead salts may 

 take place in the exposed corneal tissue in cases where 

 lead lotions are used. The bulk of the cornea is made 

 up of a great number of fibrous lamellae, between 

 which are anastomosing cell-spaces containing the 

 corneal corpuscles. If the nozzle of a fine syringe 

 be thrust into the corneal tissue, the network of cell 

 spaces can be filled with injection (Recklinghausen's 

 canals). When suppuration takes place within the 

 proper corneal tissue, it is probably along these canals, 

 modified by inflammation, that the pus spreads, thus 

 producing onyx. The cornea contains no trace of 

 blood-vessels, except at its extreme periphery, where 

 the capillaries of the sclerotic and conjunctiva end in 

 loops. This lack of a direct blood-supply renders 

 the cornea prone to inflame spontaneously in the 

 cachectic and ill-nourished. When inflamed, the tissue 

 always becomes opaque. In the affection known as 



