406 AN ADDRESS ON THE RELATIONS OF 
through the skin with a tenotome and introduce a little drainage-tube not 
bigger in calibre than a crowquill, at the same time doing this in such a way 
as to prevent the entrance of putrefaction and employing an efficient antiseptic 
dressing, we may reckon on it as a matter of certainty that the disease which 
has been previously so obstinate rapidly becomes cured. We change the dressing 
in the course of a day or two in order to shorten the tube, and at the next dress- 
ing we probably find the serous oozing has been so slight as to permit us to 
dispense with the tube altogether, and within a week or ten days the little 
puncture is healed. Meanwhile, not only is there no reaccumulation of fluid, 
but the thickening of the surrounding tissues disappears rapidly, and before 
long vanishes altogether. Let us look at the interpretation of this fact. And 
first let me remark that the treatment which so rapidly causes subsidence of 
the obstinate inflammatory disorder does not act directly upon the diseased 
synovial membrane at all. For we do not inject the antiseptic into the sac: 
all that we do is to let out the fluid and provide against reaccumulation during 
the next few days while preventing the entrance of septic material. It is, 
therefore, plain that the presence of the fluid in some way or other maintained 
the chronic inflammation. How did it do this? Not by means of micro- 
organisms, for it was clear and transparent, and contained none. Not by 
chemical irritation, as would have been the case had it contained the acrid 
products of putrefaction. Had the fluid been pus, it might have been contended 
that it might possess some slight chemically irritating property. But it was 
the bland and wholly unstimulating liquor sanguinis. We are therefore led 
safely another step, and infer that the mere mechanical presence of the fluid, 
or, in other words, the tension which it occasioned, was the efficient agent. Yet 
it is inconceivable that the inflammatory phenomena could be caused directly 
by pressure of the fluid upon the synovial surface. Synovial effusion is not as 
a matter of fact induced by mere pressure, though carried to a far greater degree 
thau the often slack collection of fluid could occasion. Or, if there be felt any 
doubt on this point, there can certainly be none with regard to the impossibility 
of the surrounding thickening being the direct effect of the pressure. We are 
therefore compelled to have recourse to the nervous system; and it is not 
difficult to understand how it is called into play, the sac being stretched by the 
accumulated fluid, and its nerves thus sufficiently stimulated to maintain the 
chronic inflammation. 
I have next to say a few words regarding suppuration. Here we have not 
only the results of antiseptic treatment favouring the idea of micro-organisms 
being its cause, but we have actual observations of such organisms present in the 
pus. Dr. Ogston, of Aberdeen, has lately made some very remarkable observa- 
