72 W. J. DA KIN. 



rays are very fine and I'emarkably definite. There are three 

 explanations of these structures that may be given. The first 

 and most unlikely is that they are artificial productions ; the 

 second, that they are modified astral rays and centrosome 

 kept permanently for another function ; the third, that they 

 are entirely different from those functioning in the cell divi- 

 sion, but have arisen iu a similar way and are purely supporting 

 fibrillae. The appearance of the structures and their presence 

 after such varied treatment is against the first view. It 

 would only be possible to demonstrate which of the latter 

 were correct if the origin of the aster had been observed. 

 I believe they are supporting fibi-illa? whatever be their mode 

 of origin, and this is Hesse's view, he considering they are 

 for the purpose of increasing the elasticity of the cells. This 

 is put forward in an interesting theory of accommodation, 

 and the fibrillae are considered to form the antagonistic appa- 

 ratus to another, to be referred to presently, which alters the 

 shape of the lens. Between the sub-corneal connective tissue 

 and the lens is a layer of peculiar fibres, first seen, though 

 incorrectly described, by Patten. He made out two layers, 

 a series of radiating fibres extending from the centre of the 

 distal surface of the lens to the periphery, superimposed on 

 a layer of strong circular fibres concentrically arranged (p. 

 581). As such do no fibres exist. Kawitz saw none here 

 Avhatever, and regarded Patten's structures as artefacts ( [25], 

 p. 113). Hesse discovered the true conditions, which I can 

 confirm with some slight additional features. There is one 

 layer of fibres only (PI. 7, fig. 8), and these have a kind of 

 spiral arrangement, so that towards the centre of the lens 

 surface they are running at almost right angles to their 

 previous course. Near the peripheiy the}^ run more or less 

 concentrically (PI. 7, fig. 8). They do not terminate at the 

 centre of this surface, but continue across for some distance, 

 and there results a series of fibres crossing one another in all 

 directions. 



In thin sections cut parallel with the plane of the cornea 

 it is possible to see a number of nuclei here, with very deli- 



