STUDIES IN THE RETINA. 319 



Without attempting in this place to review the many 

 observations of others which tend either, on the one hand, 

 to confirm, or, on the other, to make the existence of 

 this system hard to accept, I will content myself with pointing 

 out that it enables us off-hand to co-ordinate a long series of 

 observations, some of which are now universally accepted, 

 and to unite them for the first time into a connected whole. 



In the first place, it directly confirms that doctrine of the 

 essential structure of protoplasm which regards it as a 

 mitomic framework (Flemming's "Fadengerust") with "para- 

 raitomic" intervening substances (Flemming's "luterfilar- 

 substanz," the hyaloplasma of Leydig as opposed to the 

 spongioplasma). At the same time it tends to show that 

 this analysis was incomplete. For the mitomic or proto- 

 mitoraic framework as now revealed is seen to be continuous, 

 not only from cell to cell, giving thereby a new meaning to 

 the intercellular bridges which have been recorded often 

 enough to justify their claim to be of fundamental import- 

 ance, but even underlying the nuclei. That an achromatic 

 (linin) reticulum formed the basis of the nucleus has long 

 been known, and a long series of observers have seen the 

 threads of this reticulum extending beyond the nuclei, but 

 their observations have not yet gained universal credence; 

 indeed, nearly all recent cytological work seems to have been 

 of a kind that failed to make the nuclear connecting fila- 

 ments apparent. My own personal experience above described 

 will show how easily that could happen. Nevertheless they 

 exist, and the nuclei now stand in visible structural relation- 

 ship with the rest of the protoplasm. 



The best known doctrine that appeared to offer a co-ordi- 

 nation of these hitherto disconnected facts, the linin under- 

 lying the nucleus, the fibrillar structure of protoplasm, and 

 the intercellular bridges, is that of Heitzmann.-^ But this 

 doctrine will now require some modification, at least of 

 interpretation. The dictum that every cell is a " prickle 

 cell" and every nucleus a ''prickle nucleus 'Ms confirmed, 



' 'Mikroscopibclic Morphologic,' 1883. 



