On Conjoined Epithelium. By S. Martyn. 61 
The anatomical structure, then, has been described thus : the 
cells are covered more or less with spines, which, when the cells are 
isolated, show as marginal prickles ; and if the covering pressure 
chance to be nil, as besetting the surface. The spines are sharp- 
pointed, with a broadish base ; and all observers, I believe, describe 
them as interlocking with the teeth of the nest cells, thus giving 
the characteristic cohesion. Max Schultze compares this to the 
intermingled bristles of two brushes put together. Banvier speaks 
of the cells as soldered by the interlocking teeth (“ les dentelures 
au moyen desquelles elles sont engrenees et soudees”). Strieker 
uses the same phrase, and Rindfleisch compares their union to 
“ a suture ” ; and I learn that the well - known Edinburgh pre- 
par ateur Mr. Stirling, discovering them nine years ago, thought 
them like “ watch- wheels ” (see Fig. 1). 
At first sight, this all seems satisfactory enough ; but it is just 
as to the simple nature and plan of these processes that I venture 
to join issue with all observers to whose works I have been able to 
obtain access. So long, namely, as I looked at the contact between 
any two of these cells as that of toothed wheels, they really seemed 
to interlock. I confess, however, to a rooted distrust of real pro- 
cesses of definite form as being projected from a cell-wall of formed 
material, this having no analogy with the many changes of form in 
germinal or bioplastic matter. As far back as I860, when the 
language of, I believe, all the books was of processes sent out by 
cells, I ventured to dissent from such views, and, in a paper on Con- 
nective Tissue published in Beale’s ‘Archives,’ described cell-processes 
as being “ spun out ” by a receding body. This view is now 
generally accepted. It seemed, therefore, to me worth inquiry, 
whether these prickles were really processes which interlock, or 
whether they were really continuous delicate bands uniting cell to 
cell. In an epithelioma of the lip, and in a section of a hard 
preputial chancre, I found instances of a rich development of the 
prickle-cell. Probably, just as on a nasal polypus the ciliated 
epithelium often becomes monstrous, many fine examples of these 
cells may be encountered where there is unusual setting free of 
formative force. 
In the example (Fig. 2), the cell (a) is incontestably united by 
bands to its neighbours, and the decisive experiment has been 
made ; for, where these bands have broken across, the remaining 
stumps have become prickles ; but where (two cells touching) the 
teeth seem to have strongly dark ends (Fig. 2, h), I believe this 
effect is universally an optical illusion, and that the dark spot is the 
cavern between bands (b). On the other hand, where (two cells 
touching) the ordinary light spines seem to be so truncated, a very 
careful view will show that the light track may be followed from 
one cell to the next, if I may use the illustration, like walking 
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