ADDRESS. 1s 
micro-organisms concerned ; and it soon appeared that putrefaction was 
by no means the only evil of microbic origin to which wounds were liable. 
I had myself very early noticed that hospital gangrene was not necessarily 
attended by any unpleasant odour; and I afterwards made a similar 
observation regarding the matter formed in a remarkable epidemic of 
erysipelas in Edinburgh obviously of infective character. I had also seen 
a careless dressing followed by the occurrence of suppuration without 
putrefaction. And as these non-putrefactive disorders had the same self- 
propagating property as ferments, and were suppressed by the same anti- 
septic agencies which were used for combating the putrefactive microbes, 
I did not doubt that they were of an analogous origin ; and I ventured 
to express the view that, just as the various fermentations had each its 
special microbe, so it might be with the various complications of wounds. 
This surmise was afterwards amply verified. Professor Ogston, of Aber- 
deen, was an early worker in this field, and showed that in acute abscesses, 
that is to say those which run a rapid course, the matter, although often 
quite free from unpleasant odour, invariably contains micro-organisms 
belonging to the group which, from the spherical form of their elements, 
are termed micrococci; and these he classed as streptococci or staphylo- 
EE —<—— ee Ol 
cocci, according as they were arranged in chains or disposed in irregular 
clusters like bunches of grapes. The German pathologist, Fehleisen, fol- 
lowed with a beautiful research, by which he clearly proved that erysipelas 
is caused by a streptococcus. A host of earnest workers in different 
countries have cultivated the new science of Bacteriology, and, while 
opening up a wide fresh domain of Biology, have demonstrated in so many 
eases the causal relation between special micro-organisms and special 
diseases, not only in wounds but in the system generally, as to afford 
ample confirmation of the induction which had been made by Pasteur 
that all infective disorders are of microbic origin. 
Not that we can look forward with anything like confidence to being 
able ever to see the materies morbi of every disease of this nature. One of 
the latest of such discoveries has been that by Pfeiffer of Berlin of the 
bacillus of influenza, perhaps the most minute of all micro-organisms ever 
yet detected. The bacillus of anthrax, the cause of a plague common 
among cattle in some parts of Europe, and often communicated to sorters 
of foreign wool in this country, is a giant as compared with this tiny 
being ; and supposing the microbe of any infectious fever to be as much 
smaller than the influenza bacillus as this is less than that of anthrax, a 
by no means unlikely hypothesis, it is probable that it would never be 
visible to man. The improvements of the microscope, based on the 
principle established by my father in the earlier part of the century, 
have apparently nearly reached the limits of what is possible. But that 
such parasites are really the causes of all this great class of diseases can 
no longer be doubted. 
The first rational step towards the prevention or cure of disease is to 
