508 THE SOLIDS. 



which are extended in the same line. These spaces are oval 

 in the cornea, and round in that portion of the schlerotic 

 where the two structures are in connection with each other.* 

 (See Plate LXVII. fig. 3.) 



This arrangement was first pointed out by the authors of 

 the " Physiological Anatomy," and is thus described by them. 

 " On the cornea proper or lamellated cornea, the thickness 

 and strength of the cornea mainly depend. It is a peculiar 

 modification of the white fibrous tissue, continuous with that 

 of the schlerotic. At their line of junction, the fibres, which 

 in the schlerotic have been densely interlaced in various di- 

 rections, and mingled with elastic fibrous tissue, flatten out into 

 a membraneous form, so as to follow in the main the curva- 

 tures of the surfaces of the cornea, and to constitute a series 

 of more than sixty lamellae, intimately united to one another 

 by very numerous processes of similar structure, passing from 

 one to the other, and making it impossible to trace any one 

 lamella over even a small portion of the cornea. The result- 

 ing areola?, which in the schlerotic are irregular, and on all 

 sides open, are converted in the cornea into tubular spaces, 

 which have a very singular arrangement, hitherto undescribed. 

 They lie in superposed planes, the continuous ones of the 

 same plane being, for the most part, parallel, but crossing 



* A subsequent examination of the cornea renders it necessary that 

 the views above expressed of its structure should be modified to some 

 extent. I find that a considerable amount of a tissue, very closely re- 

 sembling the white fibrous tissue of the schlerotic, does enter into the 

 construction of the cornea ; in sections, however, whether treated or 

 not with acetic acid, this tissue is scarcely to be traced, the nuclear form 

 of fibrous tissue already described, and which is so very abundant, being 

 alone visible, and appearing to constitute the entire of its substance. 

 If, however, a small piece of the inner and softer part of the cornea be 

 torn up with needles, and then examined, bundles of fibrous tissue, very 

 analogous to those of the white fibrous form, will be plainly seen ; these 

 are of considerable diameter, reflect a greenish shade, and are, in many 

 parts, transversely striated, each filament bearing a resemblance to a minute 

 Conferva ; they are rendered nearly, though not quite, invisible by the 

 action of vinegar. Considered altogether, the cornea resembles very 

 closely, in structure, a tendon, which also contains a very large quantity 

 of a similar nuclear fibrous tissue. 



