Dedication requires that you turn yourself into an instrument for detection

You must not only acquire the skills and tools for detection in your domain but turn yourself into such a tool.

Detection is, or ought to be, an exact science and should be treated in the same cold and unemotional manner [SIGN].
A client is to me a mere unit, a factor in a problem. The emotional qualities are antagonistic to clear reasoning [SIGN].
I am not often eloquent. I use my head, not my heart [ILLU].
-- what your digestion gains in the way of blood supply is so much lost to the brain. I am a brain, Watson. The rest of me is a mere appendix. Therefore it is the brain I must consider [MAZA].
The price I paid for this dedication was to be viewed, even by my few intimates, as heartless. When Stamford introduced me to Watson, he said:
Holmes is a little too scientific for my tastes - it approaches to cold-bloodedness [STUD].
Watson expressed this same sentiment on a number of occasions:
You really are an automaton - a calculating machine. --- there is something positively inhuman in you at times [SIGN].
Yet, if his emotions were dulled, his intellectual perceptions were exceedingly active [VALL].
Grit in a sensitive instrument, or a crack in one of his own high-power lenses, would not be more disturbing than a strong emotion in a nature such as his [SILV].
--- his face had resumed that Red Indian composure which had made so many regard him as a machine rather than as a man [CROO].
I found myself regarding him as an isolated phenomenon, a brain without a heart, as deficient in human sympathy as he was pre-eminent in intelligence [GREE].
The state of his health was not a matter in which he himself took the faintest interest, for his mental detachment was absolute [DEVI].
Watson was most alienated from me by my dedication when I refused to congratulate him on his marriage1 , and argued instead:
But love is an emotional thing, and whatever is emotional is opposed to that true, cold reason which I place above all things. I should never marry myself, lest I bias my judgment [SIGN].
Subsequently, I whimsically assigned this domain to him,
Now, Watson, the fair sex is your department [SECO].

1   Holmes himself never married. Indeed, apart from Irene Adler, he showed little emotional interest in women. The one exception seems to have been based largely on an admiration for her intellect. She was the only person to outwit him. His life-long bachelorhood has led, in our far-from-Victorian times, to some rude speculation about the true nature of the relationship between Holmes and Watson. A product of his times, Holmes was invariably chivalrous to women, and was unconscious of the fact that this could be condescending. I doubt if he would ever have anticipated female detectives, like Sara Paretsky's V. I. Warshawsky, Amanda Cross's Kate Fansler, and so on.