254 PRACTICAL HISTOLOGY. 



membranous layer thus obtained has naturally the 

 convex shape of the cornea, and it is of course de- 

 sirable that it should lie flat upon the slide with- 

 out creases, it is well before mounting to 

 make three or four radical snips in it in 

 the way shown in the adjoining cut ; these 

 will enable it to flatten out without fold- 

 ing, when placed on the slide and covered. 

 Moreover it is important to examine the 

 object with a low power previously to covering it, 

 so that any folds of the membrane, or any foreign 

 matter or remains of epithelium adhering to it, may 

 be detected and removed. 



The remaining anterior part of cornea may be 

 further separated in the same way into lamellae, 

 which are to be mounted with the same precautions 

 as the posterior lamella. It is not always easy to 

 get them in quite so complete a layer, but for most 

 purposes a small shred will, if equally thin, show 

 nearly as much as an entire lamella. 



In all these specimens the corneal corpuscles are 

 stained of a violet color, varying in tint according 

 to the success of the preparation, their nuclei being 

 left nearly unstained. The nerves are colored almost 

 black, the fibrils looking like fine wires running 

 singly and in bundles, and provided along their 

 course with numerous minute varicosities. 



Preparation 11. The corpuscles and nerves 

 of the rabbit's cornea. The cornea of the rabbit, 

 or of any other mammal recently killed, is prepared 

 with chloride of gold in the same way as that of 

 the frog. The eyelids are first removed, care being 

 taken in doing this not to get the hair on to the 

 surface of the cornea. The eye is then to be made 

 prominent ; either by an assistant who holds it 

 firmly with forceps thrust back in the orbit, so as 

 to seize one or other of the eye muscles near their 

 attachment ; or without an assistant by clamp-for- 

 ceps, which are inserted in like manner, and by their 

 weight force the eyeball forward without unduly 



