396 EXPERIMENTAL PHARMACOLOGY 



Examine the cornea and pupil. Place the eye in a pan of 

 water and make an incision around it in the line of the 

 equator so as to separate the front half from the rear half. 

 The incision may go through all three coats, but the vitre- 

 ous humor should not be disturbed. Lift off the rear half 

 of the coats and look into the cup thus formed. What color 

 is the retina? Of what is it composed ? What drugs act on 

 the structural elements of the retina ? AVliat particular 

 parts of the retina are involved in this action ? Define the 

 optic disc and the central artery of the retina. AVliat is 

 meant by the optic cup? AVliat relation does it bear to the 

 macula lutea ? Separate the sclerotic from the choroid and 

 define the lamina fusca. Hunt for the ciliary nerves (and 

 vessels) between the sclera and choroid. How do these 

 nerves get into the eye-ball ? Define the lamina cribrosa 

 sclerse. 



Now take up the anterior half of the eye to which the 

 vitreous humor probably remains attached. Look for the 

 hyaloid membrane. "What are its functions ? To what is it 

 attached? Gently separate the vitreous humor from the 

 lens and ciliary processes and let it float in the water. De- 

 scribe its color, consistency and functions. Have you seen 

 anything of the ora serrata ? NOAV examine the ciliary 

 processes and discuss their relations to the choroid and to 

 the lens. Where are the ciliary muscle fibers? What is the 

 innervation of this muscle ? What are its points of origin 

 and of insertion? What are its functions ? What drugs act 

 on it and how do they act ? 



With care dissect away a small sector of the suspensory 

 ligament of the lens. What is the canal of Petit ? Where 

 are the spaces of Fontana located and what is their func- 

 tion? What drugs may influence this function and how? 

 What is the canal of Sclennn? Remove the entire lens. If it 

 is sufficiently transparent lay it over some small print and 

 see if the letters can be seen through the lens. How many 

 forms of lenses do vou know? To which of these does the 



