100 EVOLUTION OF THE HUMAN EYE 



H. M tiller 52 in 1858 first described how he had found flat 

 muscle fibers in the inferior orbital fissure in man, corre- 

 sponding to that met with in the orbital membrane of Mam- 

 malia. He also described how it was the antagonistic con- 

 traction of this membrane, by muscular action, which restored 

 the eyeball to its position in the socket after it had been 

 drawn back by the retractor. The muscle he found was 

 composed of unstriated fibers, and was stimulated into 

 action by irritation of the cervical sympathetic nerve. 



Sir William Turner 53 in 1862 wrote an article entitled 

 'Upon a Nonstriped Muscle Connected with the Orbital 

 Periosteum of Man and Mammals." In it he says: 'While 

 engaged in making a dissection in the human subject dur- 

 ing the winter session of last year, of the inferior maxillary, 

 or second division of the fifth cranial nerve, my attention 

 was attracted to a pale reddish, soft mass, filling up the 

 narrow chink of the sphenomaxillary fissure, and extending 

 from the sphenoid fissure in the sphenoid bone to the infra- 

 orbital canal in the superior maxillary bone. It was evi- 

 dently connected to the superior (ocular) aspect of the 

 periosteum of the orbit, and it was pierced by the orbital 

 branch of the superior maxillary nerve. Since the period 

 of making the above observation I have availed myself of 

 several opportunities of examining the same region in other 

 subjects, and have constantly observed appearances of a 

 nature similar to that just described. The amount of the 

 reddish mass and the depth of its tint varied slightly in 

 different instances. Frequently it was so pale as scarcely 

 to attract attention, which may perhaps be the reason why 

 it has so long been neglected by anatomists. When care- 

 fully examined with the naked eye, or still better with a 

 single lens, it was seen to exhibit a fibrous appearance." 



The existence of these unstriated-muscle fibers in man, 



