Chap, iv.] THE ORBIT AND EYE. 43 



suprachoroidea and lamina fusea, Y/hich are separated 

 from one another v b} v ; a lyi^ph' spaie. In injuries to 

 the globe, therefore, extensive bleeding may take place 

 between the'so^twb' epdts,' and ihdeed' a lilte hs&ncrr- 

 be' th'e v r^Jtoft sinipiy pi* ,a sucf 



hage may be' th'e v r^Jtoft sinipiy pi* ,a sucfd'ei) 

 in the ocular tension produced by such an operation 

 as iridectomy or cataract extraction. The choroid 

 alone has been ruptured (usually at its posterior part) 

 as the result of a blow upon the front of the eye. 

 The choroid is one of the few parts of the body that 

 may be the seat of melanotic growths. These growths 

 are sarcomatous tumours containing a large amount 

 of pigment, and occur only where pigment cells are 

 found. In the choroid coat pigment cells are very 

 abundant. The iris is, from its great vascularity, 

 very easily inflamed. From its relations to the cornea 

 and sclerotic it happens that inflammation in those 

 tunics can spread without difficulty to the iris. On 

 the other hand, the vessels of the iris and choroid are 

 so intimately related that inflammations set up in the 

 iris itself have every inducement to spread to the 

 choroidal tunic. When the iris is inflamed its colour 

 becomes altered, owing to the congestion of the part 

 and to the effusion of lymph and serum that takes 

 place in its substance. The swelling to which it 

 becomes subject, together with the effusion, produce a 

 blurring of its delicate reticulated structure, as seen 

 through the cornea. Owing also to the swollen con- 

 dition of the little membrane, the pupil becomes 

 encroached on, and appears to be contracted, while the 

 movements of the membrane are necessarily rendered 

 very sluggish. If it be remembered that the greater 

 part of the posterior surface of the iris is in actual 

 contact with the lens capsule, it will be understood 

 that inflammatory adhesions may readily take place 

 between the two parts (Fig. 10). After iritis, therefore, 

 it is common to find the posterior surface of the iris 



