402 THE CORNEA, BY ALEXANDER ROLLETT. 



re-dissolving in an excess of its precipitants. Brims,* how- 

 ever, obtained different results in regard to this point, but 

 found that no cartilage sugar (chondroglycose) separates from 

 corneal gelatine when this is heated with hydrochloric acid ; 

 on the other hand, he found its specific rotation to the left 

 nearly coincident with that of chondrin. Schweigger-Seidel,t 

 lastly, obtained in one instance, from corneal gelatine from 

 cornese previously submitted to the action of a ten per cent, 

 solution of common salt, the solution of which however no 

 longer gelatinised, none of the reactions of chondrin; whilst in a 

 second instance, after short duration of the action of the saline 

 solution, he obtained solutions which did do so. Our know- 

 ledge of the chemical nature of the fibrillar substance of the 

 cornea and its derivatives is therefore obviously imperfect. 



ON THE RELATION OF THE CELLS OF THE CORNEA TO THE 

 MATRIX ; INTERFIBRILLAR PORTION OF THE MATRIX AND THE 

 SPACES IN THE LATTER. Natural cavities in the matrix of the 

 cornea occur only in the form of the serous canals (Saftcanal- 

 chen, Hornhauthohlen) demonstrated by v. Recklinghausen,| 

 and these enclose the cells of the cornea. 



The serous canals were first examined with precision in 

 cornese treated with solution of nitrate of silver. 



The results of the treatment of the cornea with nitrate of 

 silver, when successful, appear to me to be very satisfactory, 

 if we disregard the chemical changes that are produced. 



Unsuccessful silver preparations cannot however, I think, 

 be held to possess a higher value than unsatisfactory specimens 

 prepared by any other mode of histological research. 



Let us commence with the consideration of negative (| 

 silver preparations. Very beautiful ones may be obtained by 

 immersing the perfectly fresh cornese of all kinds of animals 



* Loc. Git., p. 263. 

 t Loc. cit., pp. 355 and 356. 

 Die Lymphgefasse, etc., pp. 36 52. 



I should not, however, make the same statement in regard to the 

 indications of structure produced by silver in other tissues. 

 || Leber, loc. cit. 



