You can do nothing as a student in practice without it. Carry a small note-book which will fit into your waistcoat pocket [in these days an iPad or equivlent], and never ask a new patient a question without note-book and pencil in hand……Begin early to make a three-fold category – clear cases, doubtful cases and mistakes. And learn to play the game fair, no self-deception, no shrinking from the truth; mercy and consideration for the other man, but none for yourself, upon whom you have to keep an incessant watch. You remember Lincoln’s famous mot about the impossibility of fooling all of the people all of the time. It does not hold good for the individual, who can fool himself to his heart’s content all of the time. If necessary, be cruel; use the knife and the cautery to cure the intumescence and moral necrosis which you feel in the posterior parietal region…It is only by getting your cases grouped in this way that you can make any real progress in your post-collegiate education; only in this way you gain wisdom with experience. etc, etc. [all of this is very good and important]
Now... translate this into 21st Century reality with out electronic tools and it is even more powerful.