PRESIDENTS ADDRESS. 723 
er infection. Coincidence is the bane of scientific investi- 
gations and statistical conclusions. Out of the long list of 
diseases that the preceding generations of physicians, for 
want, perhaps, of some more definite cause, was always con- 
sidered to be part and parcel of the individual, and derived 
- from his parents. 
The neurotic then remain, in my opinion, the only dis 
orders, excepting syphilis, that are not accidental or ac- 
quired. That this represents a great revolution in thought 
it not to be gainsaid, when we consider how seldom children 
in facial /likeness, form, height, or character resemble their 
parents, and how, in animals, the most careful selection in 
breeding and mating so rarely produces similarity. So 
many other causes come into play in the determination of 
the individual, of which soil is not the least, and in the pro- 
duction of disease, ventilation, and food play so great a part 
that we can understand why disorders are not so frequently 
transmitted as our fathers thought. 
Age, sex, and temperament are other intrinsic factors 
which have their bearing in this connection. These were 
well-known to.our predecessors, but what they were totally 
unacquainted with is the powerful influence of the secretions 
of, until recently, apparently unimportant glands. Who, 
a few years ago, would ever have thought that life could not 
exist without the coloid product of the thyroid? The same 
with the supra-renal capsules, and it would seem that hyper- 
trophy of the pineal is accompanied, like the others, with its 
own peculiar malady. Depend upon it, there is a great 
future in the elaboration of the uses of these various secre- 
tions, of which bile is one. This fluid, at once an excre- 
tion and a secretion, must play a great part in the welfare 
of the economy; and what its function is as regards the 
latter has, as you are aware, never been determined. 
Let us pass now to the intrinsic causes of disease. Here, 
I naturally desire to emphasise the part the bacillus plays. 
When I was a student, the germ had no place in the invest# 
gation of etiology. Parkes, the most distinguished Professor 
of Hygiene that the last century produced, in 1866, in his 
address to the probationers at the Mailitary School of 
Medicine, laughed at the idea of the microbic nature of the 
exanthemata. He said—‘‘ Microscopic power has been so 
extended that the hand can now be magnified to the size of 
Mont Blanc, and nothing has been revealed which could for 
a moment lead one to suppose that germs had any relation 
to the cause of disease.’”’ He considered that labour in this 
direction was energy thrown away, and advised his héarers 
to discard such new-fangled theories as nonsense. This, of 
