STUDIES IN THE RETINA. 67 



well-known figures of " fixed morphological elements " re- 

 vealed by the method, we find not only the "dendrites/' but 

 also the " Miiller's fibres " in their most developed form, and 

 the " rod fibres " with their terminal swellings all equally 

 clearly shown. The interpretation which we have put upon 

 the latter two makes it more than probable that a proportion 

 at least of the " dendrites " are also nothing but the parts of 

 streams already so frequently alluded to in the foregoing 

 pages. I say a proportion of the " dendrites " for reasons 

 which will be made clear in another paper, in which I shall 

 also show that the nerve-paths through the retina can be 

 demonstrated by ordinary methods of staining, and that they 

 have no connection whatever with the "dendrites." 



Summary. 



As the results so far attained in the preceding five parts of 

 these studies are largely hidden under a mass of minute histo- 

 logical detail, it is better, at this stage, that a summary be 

 given of the more important. In the next paper we shall deal 

 with the question of the nerves, which naturally has a much 

 wider bearing than any detail of retinal structure merely as 

 such. 



The conclusion which of all others now arrived at is of 

 widest significance from a general point of view, is that the 

 retina can no longer be regarded as built up of so many 

 separate " cells," each with some definite and permanent 

 morphological value. This view, which has always been taught 

 hitherto, has recently to all appearance been strongly confirmed 

 by means of the metal impregnation method. This appears 

 to reveal several distinct types of cells mainly distinguishable 

 by their positions and by the different forms assumed by the 

 ramifications of their respective cytoplasms. It is now main- 

 tained, indeed, that these cells, to which special names have 

 been given, have distinct and definite functions, so that if one 



