president's address. 
17 
death. It is conjectured that they elaborate some toxic principle 
in the blood which gradually poisons the whole system. This 
toxic principle may very possibly be some product of their own 
decomposition; just as man himself secretes a noxious elfete 
principle, called urea, which, if retained in his blood, speedily 
brings about his dissolution. It is even supposed this toxic 
principle may be the ultimate cause of the death of the microbes 
themselves, and the patient’s final recovery. To adopt the 
trenchant language of Prince Bismarck, nature leaves them to stew 
in their own juice. It seems to be a neck-and-neck race between 
the microbes and the patient, which shall hold out the longest. 
If the microbes sicken and die first, the patient recovers; if the 
microbes, on the contrary, retain their vitality, the patient succumbs. 
This is, no doubt, a somewhat crude pathology, but I suspect there 
is an element of truth in it. 
The pathogenic bacteria are still masters of the field, not- 
withstanding all the efforts of their enemies, the bacteriologists. 
However, the latter are diligently taking the measure of their 
adversary, and endeavouring to find out some loop-hole in his 
defensive armour. If it has cost electricians, such as Edison, 
years and years of patient study and experiment to perfect the 
electric light, bacteriologists must not expect to solve their far 
more complex and difficult problem in a single decade. One thing, 
at least, is certain, that we stand on far more solid ground than 
our predecessors did. We, at least, know with what we have to 
deal. We can put our enemy in a cage, as it were, feed him with 
the bread and water of affliction, and see what he can and what he 
cannot stomach. We have no longer to deal with a set of vague 
symptoms, the mere outward manifestation of the disease, but with 
the veritable essence of the disease itself. Hitherto the besiegers 
have limited their offensive operations to the mere outworks of 
disease, but henceforth the citadel itself will have to bear the brunt 
of battle. 
VOL. v. 
c 
