ves. Of course there may be also an irritation of the nerves, but
this, if we do not take function into account, has no causal connection
with the processes going on in the tissue proper, but is merely a
collateral effect of the original disturbance.

Besides these active processes of function, nutrition, and new
formation, there occur passive processes. Passive processes are called
those changes in cells whereby they either lose a portion of their
substance, or are so completely destroyed, that a loss of substance, a
diminution of the sum total of the constituents of the body is produced.
To this class belong fatty degeneration of cells, affection of arteries,
calcification, and ossification of arteries, amyloid degeneration, and
so forth.

It will now be necessary to consider inflammation at more length. The
theory of inflammation has passed through various stages. At first heat
was considered as its essential and dominant feature, then redness,
then exudative swelling; while the speculative neuropathologists
consider pain the _fons et origo_ of the condition.

Personally, I believe that irritation must be taken as the
starting-point in the consideration of inflammation. We cannot conceive
of inflammation without an irritating stimulus, and the first question
is, what conception we are to form of such a stimulus.

An inflammatory stimulus is a stimulus which acts either directly or
through the medium of the blood upon the composition and constitution of
a part in such a way as to enable it to attract to itself a larger
quantity of matter than usual and to transform it according to
circumstances. Every form of inflammation with which we are acquainted
may be explained in this way. It may be assumed that inflammation begins
from the moment that this increased absorption of matters into the
tissue takes place, and the further transformation of these matters
commences.

It must be noticed that hyperaemia is not the essential feature of
inflammation, for inflammation occurs in non-vascular as well as in
vascular parts, and the inflammatory processes are practically the same
in both instances.

Nor is inflammatory exudation the essential feature of inflammation. I
am of the opinion that there is no specific inflammatory exudation at
all, but that the exudation we meet with is composed essentially of the
material which has been generated in the inflamed part itself, through
the change in its condition, and of the tran