THE PROPER TISSUE OF THE CORNEA. 385 



in water acidulated with a little acetic acid, when it rapidly 

 assumes a reddish or bluish colour. If now, in the course 

 of a few days, and with the addition of a little glycerine, 

 the specimen be examined under the microscope, after the 

 anterior epithelium has been brushed off, the most beautiful 

 results in regard to sharpness of outline and minute detail are 

 obtained, the cell-plexus appearing tinted of a red or blue 

 colour by the reduced gold (fig. 380, a). 



Thin vertical sections of such cornese may be made with great 

 success, showing the course of the processes of the corpuscles. 

 These may be observed traversing the cornea in all directions. 

 When seen lengthwise, they appear still in connection with the 

 nucleated central mass, or we may meet with longitudinally, 

 obliquely, or transversely divided fragments (fig. 380, 6). 



It is also very instructive to tease out both surface and 

 vertical sections of corneas stained with chloride of gold, and to 

 examine the behaviour of the cells and their processes, and this 

 is particularly requisite in regard to the mutual relations of 

 the cells and matrix which will be presently discussed, 



Gold preparations of the cornea of the most diverse animals 

 give, when successful, images that essentially correspond to the 

 cell-plexus of the cornea of the Frog, which is so far important, 

 as we have the best opportunity in the cornea of this last- 

 named animal of satisfying ourselves that the corpuscles make 

 their appearance in precisely the same manner, except that 

 they are coloured, as when other methods of preparation are 

 employed. And just as in the corpuscles of the earlier men- 

 tioned preparations, so also in those of the gold preparations, a 

 thorough and complete similarity is discernible between the 

 cell-substance collected around the nucleus and the substance 

 of the processes. 



There are yet other methods of impregnating the cornea with 

 metallic salts, as by treatment with nitrate of silver (Coccius,* 

 His,t v. Recklinghausen),J and also by impregnation with iron, 



* M. C. A. Flinzer, De Argenti nitrici usu et effectu, etc. Lipsiae, 1844. 

 Dissert, inauguralis. 



t Loc. cit., p. 67 ; Virchow's Archiv, Band xx., p. 207 ; Schiceizerische 

 Zeitschrift fur Heilkunde, Band ii., No. 1. 



. Virchow's Archiv, Band xix., p. 451 ; Die Lympligefasse und ihre 



VOL. III. C C 



