The Eye of tie God-fish. 201 



"Eye," in Dr. Todd's Cyclopcedia of Anatomy and Physio- 

 logy, he simply observes : — " The organization of the part is 

 certainly not merely vascular, as stated by Cuvier, and un- 

 doubtedly bears a stronger resemblance to muscular than any 

 other structure ; it also retains the peculiar colour of red muscle 

 after all the rest of the eye has been blanched by continued 

 maceration in ■water." 



On recently consulting Leydig's Lehrbuch der Histologie, 

 I was surprised not to find any description of the organ, in 

 question, which is the more remarkable as the author has given 

 a good account of the processus falciformis and campanula Hal- 

 leri. It seems, therefore, that the now very generally received 

 opinion as to the erectile character of the so-called choroid gland 

 is still deemed worthy of credit, and further, that in virtue of 

 its erectile properties, it is, to use Dr. Carpenter's words, "con- 

 cerned in the adaptation of the eye for distinct vision at differ- 

 ent distances." To me it appears that a due consideration 

 of the facts and arguments which I shall immediately re- 

 cord, are sufficient to demonstrate the erroneousness of these 

 views. 



If the perfectly fresh eye of a full-grown cod be removed 

 from its socket, three large vessels will be seen to enter or 

 emerge from the sclerotic covering ; namely, a vein passing out 

 from within the optic sheath, an artery entering immediately 

 behind the sheath, and a vein situated further back, at a little 

 distance from the circumferential border of the tunic. If the 

 loose cellular connective tissues be next dissected off from the 

 sclerotic, the latter will be found to consist of three distinct 

 layers ; that is to say, of an outer and inner fibrous membrane 

 which inclose between them the true cartilaginous coat. The 

 first-mentioned layer consists of coarse fibrous tissue closely 

 investing the cartilage, but the internal connective layer is 

 delicate, transparent, and easily separable from the middle coat. 

 A thin verticle section of the latter, or true sclerotic layer, dis- 

 plays, under the quarter-inch objective, a hyaline, ground-glass- 

 like matrix, in which the characteristic cartilage cells are 

 numerous, thickly set, and rather irregularly disposed. 



In addition to these ordinary structural characters, it is not 

 uncommon to find, especially in old fishes, milky- white patches 

 partially or entirely embedded in the cartilaginous matrix, and 

 they not unfrequently project considerably from the inner true 

 sclerotic surface. These striking-looking patches vary in size 

 from a pin's head to that of a threepenny -piece, and invariably 

 present a more or less rounded, oval, or semicircular outline, 

 the borders of which are usually cleft and lobed in so regular 

 a manner that the entire mass frequently exhibits a curiously stel- 

 late appearance, such as is accurately represented in the accom- 



