142 TRUTH, PATHOLOGY, AND PUBLIC. 
promising physicians, will be superseded, it may 
be, in a very few years; but if you have learned 
the scientific method, you will help, by patient 
and accurate observation and thought, progress 
which shall endure when much crude innovation 
known by the name shall have been abandoned 
and forgotten. 
How hard it is to be accurate! Nay, rather how 
impossible! Accuracy is approached as if by a 
process of dividing the distance. Constant effort 
produces constant progress; but a fraction of the 
distance continually remains. At least, so it is in 
matters of observation and construction. We begin 
them with a preconceived notion as to the degree 
of exactness required ; as we proceed we find we 
have to amend our notions; and when we have 
done this several times we find it exceedingly 
difficult or even impossible to recall the state of mind 
from which we started. Turn back your minds 
to the first few days of your studentship, and try to 
realise your first impressions of, for example, a verte- 
bral column. Probably you thought that nothing 
could be easier to understand, but wondered at the 
tiresomeness of detail in the descriptions given by 
authorities. You will probably also recollect that 
your teachers took a great deal of trouble to con- 
vince you of the importance of much which you 
