410 THE CORNEA, BY ALEXANDER ROLLETT. 



Different results, however, are obtained with different animals. 

 In the cornea of the Sheep, Ox, Rabbit, and Frog, we obtain 

 parallel and fasciculated figures, in close juxtaposition to one 

 another, and separated by only very narrow intervals, which 

 run out like spear-heads, and present constrictions of various 

 extent, but rarely communicate transversely. Such fasciculated 

 figures decussating at various angles are superimposed upon one,, 

 another. 



In the Frog, where the injection, although troublesome to 

 effect, yet in some cases succeeds very well, the constrictions in 

 the spear-like figures appear to follow one another quickly, 

 whilst the intervening portions are relatively short. We thus 

 obtain the appearances represented under a low power in 

 fig. 386. 



Fig. 386. 



Fig. 386. Corneal tubes of the Frog, as seen on injection with an 

 oily fluid. 



All injections succeed best in perfectly fresh cornese, and 

 these should be examined in the aqueous humour immediately 

 after the injection has been made (with Hartnack's objective 

 No. 4, and ocular No. 3, and with gradually increasing powers). 

 If now we compare the appearances obtained by means of 

 injection in the Frog with the silver or gold specimens, and 

 form an unbiassed opinion respecting them, it is difficult to 

 explain why the corneal tubes and serous canals have not 

 always been considered fundamentally distinct things. 



But as in Frogs, so is it also in all the above-named animals. 



The appearance presented by the injected cornea is, however, 

 different from this in the Dog and Guinea-pig ; for here the 



