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form, which become smaller as they approach the ciliary ligament, 

 where they terminate in a circular vein surrounding the cornea. The 

 rapid circulation of the blood at the apparent extremities of the ves- 

 sels over the inner parts of the cornea, indicates their further con- 

 tinuation inwards or below, although the author has not traced them 

 further over the cornea. 



The vessels of the anterior surface of the iris, which Dr. W. 

 next examines, consist of arteries and veins. The former are derived 

 almost entirely from the two long ciliary arteries which arrive near the 

 outer and inner angles of the eye, their course being traced over the 

 anterior half of the sclerotic until they reach the great circumference 

 of the iris, where they each subdivide into two equal branches, one 

 inferior, the other superior, which diverge at an obtuse angle, each of 

 them running in an oblique direction towards the edge of the pupil 

 until they attain the inner third of the iris, where most of the final 

 subdivisions are bent outwards. These four oblique branches forma 

 symmetrical figure of a lozenge-shape over the iris, each branch 

 giving off internal and external twigs, the former ending in the small 

 circumference, the latter in the large circumference of the iris. The 

 course of the blood may be watched in these vessels from over the 

 sclerotic to their termination in the iris, but in general the current 

 is too rapid to allow of the detection of the direction of the separate 

 particles of the blood. It is only when the circulation becomes lan- 

 guid that the separate globules can be seen distinctly running in a 

 centrifugal (i. e. arterial) direction. 



By compressing the eye slightly, the passage of the blood may be 

 retarded, and by that means be easily followed ; but in so doing an 

 error may possibly be committed respecting the arterial nature of 

 these vessels, as the course of the blood is then generally reversed in 

 the arteries, and will be seen to take a centripetal direction, sometimes 

 for upwards of a minute, according to the amount of pressure. But 

 in a short time, after oscillating within the vessels, the blood again 

 resumes its natural course, which may be sufficiently regulated to 

 enable us to watch the passage of the globules in the oblique branches 

 and in their internal and external subdivisions. 



The veins of the iris form two layers. The superficial layer com- 

 prises all the larger veins generally twenty-three or twenty-four 

 in number, which radiate in a regular manner from the pupil out- 



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