262 PRACTICAL HISTOLOGY. 



oval nuclei are seen in the lamina, which are appa- 

 rently devoid of cell-body. These are in reality the 

 nuclei of epithelioid cells which bound the lamina 

 suprachoroidea externally, and serve as part of the 

 lining of the lymphatic space which lies between 

 this and the lamina fusca of the sclerotic. Their 

 outlines cannot be brought to view without the aid 

 of nitrate of silver, and the cell-bodies are too deli- 

 cate and transparent to be shown by the present 

 mode of preparations. A large number of elastic 

 fibres are also seen on the membrane, especially at 

 the terminations of the fibres of the ciliary muscle, 

 where they appear to come in relation with the ends 

 of these, an elastic fibre passing for a certain dis- 

 tance along each side of the muscular fibre, and 

 seeming to serve in this way for its attachment. 

 The involuntary fibres are particularly well shown, 

 their nuclei being conspicuously stained by the log- 

 wood ; many of the bundles terminate in peculiar 

 tufts, from which the fibres radiate in all directions. 

 It may happen that the preparation includes one of 

 the long ciliary nerves ; this, as it coursed forward 

 to enter the ciliary muscle, having been torn away 

 with the shred of membrane. If so, it may be fol- 

 lowed with the microscope and its branches traced 

 amongst the bundles of muscular fibres, forming a 

 plexus with those of the other nerves. In tracing 

 the branches characteristic ganglion-cell enlarge- 

 ments will here and there be found interpolated in 

 the course of a nerve fibre. 



Preparation 18. Vascular layers of choroid 

 and membrane of Bruch. As seen in the prepara- 

 tion just described, it is easy to detach the lamina 

 suprachoroidea from the rest of the choroid. The 

 other three parts are more difficult to separate, and 

 their complete isolation may require considerable 

 time and patience. But for demonstrating their 

 structure it is not absolutely necessary for them to 

 !>< completely separated as distinct membranes ; it is 

 sufficient if, in a piece which includes all, one or 



