ON THE PHAGOCYTES OF THE ALIMENTARY CANAL. 489 
deep violet-blue. Some are, of course, of a slightly darker hue 
than others, but one never sees any degenerated organisms 
such as will be described later on ; these forms of degenera- 
tion being only found in microbes which have been 
taken into the interior of living micro- or macro- 
phages. 
The leucocytes found between the epithelial cells occasion- 
ally contain numerous microbes and are therefore true micro- 
phages. There can be no doubt that the micro-organisms 
really le in the interior of these cells, and not simply above 
or below them. As a rule they do not show any signs of 
degeneration as long as the microphages are still placed 
between the epithelial cells. Most of the microbes present in 
the cells are short, though some of them are of very large size 
(see figs. 8, 8 dts, 9). On the other hand, micro-organisms are 
never found in the epithelial cells except occasionally in one 
which had undergone mucoid degeneration. They are not 
found lying free between the epithelial cells, for, when there, 
they are always enclosed in a leucocyte. On_ superficial 
examination the epithelial cells sometimes appeared to contain 
microbes, but a closer scrutiny showed that these were always 
at a higher or lower level than the latter, and had been carried 
into that position by the knife or by some other artificial 
means. Of course, every leucocyte found in the epithelial 
border does not always contain microbes, but it is only now 
and then that such a one is met with. 
Let it be stated here that these facts may be observed in all 
the Peyer’s patches of rabbits wherever these are present in 
the intestinal canal, but the formation of macrophages and the 
destruction of microbes take place far more actively in some of 
them. ‘The patch placed near the rabbit’s ilio-cecal valve and 
the vermiform appendix are the structures in which these pro- 
cesses are most marked. Whereas in the lymphoid patches of 
the small intestine six to twelve bacilli only may be present in 
one field of the microscope (oc. 3, obj. =4, Vérick), I have 
counted more than two hundred micro-organisms in a single 
field of the deeper layers of the vermiform appendix, 
