430 NERVOUS SYSTEM. 



appears to me to be very strongly marked; for, notwithstand- 

 ing its immersion in spirits of wine, it retains its transparency. 

 It is hard and elastic, and when clipped with the scissors, gives 

 nearly the same sensation as the thin paring of a finger nail 

 would; or, as has been observed by Elaller, it, in this respect, 

 resembles the cornea. The analogy with the cornea ceases, 

 however, at this point; for the cornea has always so much al- 

 buminous matter in it as to be rendered turbid when it is 

 immersed in alcohol. The- posterior section of the capsule 

 of the lens, is not so well marked either by its thickness or 

 specific characters as the anterior, yet our preparations in 

 the University demonstrate its existence equally as conclu- 

 sively. It is more assimilated to the nature of the tunica hy- 

 aloidea. 



In the injected foetal eye, the artery of the tunica hyaloidea 

 which comes from the central one of the retina, is seen to fur- 

 nish several minute ramifications to the posterior face of the 

 lenticular capsule; some of its branches also go to the front of 

 the capsule, but the latter part is furnished principally by arte- 

 rioles from the ciliary body of the choroides. The two sets of 

 arteries anastomose with each other; some of the latter are also 

 spent upon the membrana pupillaris. 



The point is yet doubtful whether any of these arteries pe- 

 netrate into the body itself of the crystalline humour. Ruysch, 

 Albinus, and Haller, assert the fact of their having seen and 

 injected them in the human species and in animals, and J. F. 

 Meckel admits their testimony. Yet there are not many ana- 

 tomists who can corroborate it by their personal observations. 

 It is sufficiently reasonable to admit it; for without, we cannot 

 conveniently account for the growth and nutrition of the lens, 

 as well as the morbid changes which occur in it. It should be 

 observed that if this vascular connexion do exist, it is a very 

 weak one: for the lens seems to be simply surrounded by its 

 capsule without adhering to it. 



Some veins which discharge into the veins of the choroid 

 coat, have been observed by Walter* on the posterior part of 

 the capsule. It should be continually borne in mind that nei- 

 ther the arteries nor veins of the healthy crystalline, nor of its 



* De Oculis. Berlin, 1778. 



