10 
J. C. DALTON. 
granted. But, furthermore, I believe there are two things upon 
which your future success will mainly depend. 
The first is, the accuracy of the knowledge which you ac¬ 
quire on any particular subject. There is a great difference in 
this respect. One man will learn a thing and remember it pretty 
well in a general way, but without having any very definite idea 
of the. particulars. Another will do it so that he knows exactly 
how much he has learned, and what the evidence of it was, and 
what are the figures and quantities essential to the result. He 
knows precisely where his information on that subject begins and 
where it ends; how much of it is certain and how much doubtful. 
How that is the only kind of knowledge that will be of much 
use in the long run. It is harder to acquire, of course; but it is 
worth a great deal more after you have got it. And where two 
men come in contact, if the knowledge possessed by one is indefi¬ 
nite and that of the other exact, there is no doubt at all which of 
them will carry the day. Natural quickness or facility of 
apprehension is a good thing, but it will not compensate 
for the want of precise knowledge. It is better to make a mis¬ 
take and have a good reason for it, than to guess right not 
knowing why. And the reason is that when a man with the 
right kind of knowledge makes a mistake, he finds out that he 
has made it, and what is more, he knows why he made it, and 
just where the difficulty was. Such a man is always improving; 
and at the end of ten years, in the slow race for superiority, he 
will have passed his clever competitor and left him out of sight. 
The second quality which is of most value for a practitioner, 
and for his patients too, is what we call a good judgment. In 
common parlance, it is spoken of as a “level head.” I do not 
know how that phrase originated, but it conveys the idea ex¬ 
tremely well. It means the power and habit of appreciating 
what is really important in a thing and what is not; of paying 
attention to what a thing is, rather than to the name it goes by; 
and of distinguishing, among several causes, which is the real 
one, and which are only incidental. The man who does this 
takes hold of his business by the handle, and will probably 
accomplish something; because the result he gets, if he succeeds 
