/ http://www.slideshare.net/images/logo.gif / 際際滷Share feed for 際際滷shows by User: babupmohan https://public.slidesharecdn.com/v2/images/profile-picture.png I knew that seclusion and solitude were very necessary for my friend in those hours of intense mental concentration during which he weighed every particle of evidence, constructed alter- native theories, balanced one against the other, and made up his mind as to which points were essential and which immaterial. I therefore spent the day at my club and did not return to Baker Street until evening.