of Bacteria and their Allies by Heterogenesis. 4.03 
Every section, however, showed, inside the area which had 
been affected by the chromic acid, that almost every cell 
within the renal tubules was full of developing or actually 
developed Bacteria. The former appeared as mere cocci- 
like particles which had taken the stain like the developed 
Bacteria, both being situated in the midst of cell-granules 
comparatively unstained. ‘The organisms were distributed 
through the substance of the cells, but often seemed to be 
most abundant in the half of the cell next the wall of the 
tubule, as may be seen in the transverse and longitudinal 
sections of tubules shown in P]. XXVI. fig. 11, A, B ( x 700). 
In a few of the tubules in the pyramidal portions of the kidney 
the organisms had developed more abundantly, so that the 
cells were filled with a dense mass of Micrococci such as may 
be seen in fig. 12, A (x 700). In sections through blood- 
vessels also a moderate number of Bacteria were seen mixed 
with the blood-corpuscles. 
Here, then, it is clear that we have again the kind of 
appearances which we have a right to expect if the micro- 
organisms had developed in the epithelial cells of the kidney 
by heterogenesis. We have the cells full of particles 
developing into fully formed Bacteria, and, what is more 
important still, we have them within almost every epithelial 
cell to be seen in the sections. 
From the point of view of the really absurd suggestion as 
to organisms being found in such an abdominal organ as the 
kidney, by reason of its “proximity to absorbing mucous 
membranes,” it may be well to recall the fact that the sheep’s 
kidney is encased in a mass of fat from half an inch to an 
inch in thickness, and that, as an additional barrier separating 
wandering microorganisms from the epithelial cells of the 
organ, there is still the thick and tough capsule which I have 
thought it not useless to show in fig. 12, B (x 700). Let 
anyone compare M. C. Potter’s description (p. 385) of the 
mode in which Bacteria are enabled to effect an entry into a 
single vegetable cell, and then let him imagine what an arm 
of Bacteria would be needful, with all the cytase that they 
could excrete, to get through such a tough and thick layer as 
that presented by the fibrous capsule of the kidney. But 
surely the whole notion as to such a mode of infection of the 
kidney and other abdominal organs is too absurd for serious 
consideration. 
We are then driven back to enquire whether it is true 
that the blood is germless, and whether it has in reality the 
bactericidal qualities with which it is credited. I have no 
evidence whatever to oppose to these beliefs, nor is it easy 
