RELATIONS OF CORNEAL CORPUSCLES TO MATRIX. 407 



it may be traced into the processes radiating from the cavity. 

 On the whole, the relation of the protoplasm to the cavities of 

 the matrix is in these cases very similar to that which obtains 

 in many cases of foetal bone between the bone cavities and the 

 contained cells. 



We see, therefore, that in successful specimens obtained by 

 this method, and, as I have said, success is almost constant, the 

 correctness of my statements is confirmed. The appearances in 

 question are best seen with an immersion lens of high power. 

 The irritated cornese should be quickly treated with iodine 

 vapour, or they may be submitted to the action of gold, and 

 the appearances then presented may be compared with those of 

 the unexcited cornea, and no doubt can be felt in regard to 

 their relations. The cavities of the cornea which are thus 

 rendered visible, cannot be explained by attributing them to 

 any special arrangement or disposition of the fibrillar substance 

 of the cornea alone. 



Either there is in the tissue of the cornea a system of canals 

 bounded by a special membrane, from the interior of which the 

 protoplasm can retract, and which either constitutes a distinct 

 entity, or is firmly connected on its exterior with the fibrillar 

 substance, or the cavities of the cornea are imbedded in a sub- 

 stance intermediate to the fibrils and fasciculi of fibrils. The 

 cavities form a plexus with dilated nodal points traversing 

 this substance ; and this system of cavities is under certain cir- 

 cumstances completely, under others incompletely filled, by the 

 protoplasmic plexus of the corneal corpuscles. 



No membrane answering the former description, and repre- 

 senting a special cell membrane or encysting membrane of 

 the cell plexus of the cornea, can be ascertained to be present 

 either by double contours in optical section, or in the broken 

 and teased-out felt of the ruptured membrane. On the other 

 hand, the appearances presented by the irritated fresh cornea 

 are completely in accordance with the second of the above- 

 mentioned views. 



The significance of the appearances seen in silvered and 

 otherwise tinted cornese always looking at them from a 

 morphological point of view presents no difficulties, if we 

 remember simply the three factors of the protoplasmic plexus, 



