In the Sherlock Holmes stories
Brother of Sherlock Holmes. (BRUC, 29)
He was 7 years older than Sherlock Holmes (GREE, 23). He was a much larger and stouter man. His body was absolutely corpulent, but his face, though massive, had preserved something of the sharpness of expression which was so remarkable in that of his brother. His eyes, which were of a peculiarly light watery grey, seemed to always retain that far-away, introspective look which could be only observed in Sherlock's when he was exerting his full powers (GREE, 60). He was very massive (FINA, 200), tall and portly, heavily built and massive, there was a suggestion of uncouth physical inertia in the figure, but above this unwieldy frame there was perched a head so masterful in its brow, so alert in its steel-grey, deep-set eyes, so firm in its lips, and so subtle in its play of expression, that after the first glance one forgot the gross body and remembered only the dominant mind (BRUC, 136).
He possessed in a larger degre the faculty of observation and deduction than his brother Sherlock Holmes (GREE, 13). He had no ambition and no energy (GREE, 38).
He lodged in Pall Mall (FINA, 166), and he walks round the corner into Whitehall every morning and back every evening. From year's end to year's end he takes no other exercise, and is seen nowhere else, except only in the Diogenes Club, which is just opposite his rooms. (GREE, 46)
He took snuff from a tortoiseshell box and brushed away the wandering grains from his coat with a large, red silk handkerchief (GREE, 103). And he smoked (GREE, 319)
He was very wellknown in the Diogenes Club (GREE, 27) and one of the queerest member (GREE, 29). He had an extraordinary faculty for figures, and audited the books in some of the Government departments (GREE, 45).
He was one of the founders of the Diogenes Club. (GREE, 55)
he had some office under the British Government (BRUC, 49), and occasionally he WAS the British Government (BRUC, 54). He drew four hundred and fifty pounds a year, remains a subordinate, has no ambitions of any kind, would receive neither honour nor title, but remained the most indispensable man in the country (BRUC, 57).
His position was unique. He has made it for himself. There has never been anything like it before, nor will be again. He has the tidiest and most orderly brain, with the greatest capacity for storing facts, of any man living. The same great powers which his brother have turned to the detection of crime he has used for this particular business. The conclusions of every department were passed to him, and he was the central exchange, the clearing-house, which made out the balance. All other men were specialists, but his specialism was omniscience. When a Minister needed information as to a point which involved the Navy, India, Canada, and the bi-metallic question, he could get his separate advices from various departments upon each, but only Mycroft could focus them all, and say off-hand how each factor would affect the other. They began by using him as a short-cut, a convenience, he has made himself an essential. In that great brain of his everything was pigeon-holed, and could be handed out in an instant. Again and again his word has decided the national policy. He lived in it. He thought of nothing else save when, as an intellectual exercise, he unbended if Sherlock Holmes called upon him and asked him to advise him on one of his little problems. (BRUC, 59)
Relationship with Sherlock Holmes
He heard of Sherlock everywhere since Watson became the detective's chronicler. (GREE, 64)
He disguised as a cabman to drive Watson at Victoria Station to meet Sherlock Holmes (FINA, 200 & 244).
While Sherlock Holmes was away from England during the Hiatus, he managed the Sherlock Holmes' properties (FINA, 402), and he was his only contact (EMPT, 175).
When Mycroft visited Sherlock, the later called him Jupiter. (BRUC, 72)