Sherlock Holmes’s own wide knowledge of classic murder cases and of the circumstances of their victims’ demise certainly assisted him in the detection of crime and the speed with which he reached his conclusions.
Sherlock Holmes was a Reader
In A Study In Scarlet, Holmes mentions that “The forcible administration of poison is by no means a new thing in criminal annals. The cases of Dolsky in Odessa, and of Leturier in Montpellier, will occur at once to any toxicologist.” One suspects that the Commonplace and other books which cluttered the interior of 221B Baker Street, far from gathering dust, were stuffed to the brim with excerpts from The Police Gazette and cuttings from the newspaper reports of sensational murder trials of the period. And Holmes’ brain was, we recall, like an attic, from which all types of useful data could be extracted in order to provide a useful comparison.
Sherlock Holmes Understood Crime Patterns
Any criminologist knows that the existence of a pattern in the crime of murder is of supreme importance to the investigator. And the recognition of a pattern in the early stages of an investigation gave Holmes an advantage over the official police force of the day, whose methods lacked a definite system. It is therefore not surprising that he was once compared to Alphonse Bertillon, the great French criminologist. Holmes recommended that the most practical thing a detective could do was to “shut yourself up for three months and read twelve hours a day at the annals of crime,” and pointed out that “It’s all been done before, and will be again.”
Holmes Made it his Job to be an Expert in Criminology
For that reason, he spent much of his professional career absorbing and becoming an expert upon a wide range of specialised knowledge, including tobacco ashes, cryptography, newspaper types, perfumes, toxicology, the dating of documents, the typewriter and its relation to crime, bicycle tyres, tattoos, footsteps, the influence of the trade on the form of the hand, and the names and trademarks of the world’s major gunmaking firms. He also showed considerable interest in anatomy, an interest which Watson described as “accurate but unsystematic,” and twice applied this knowledge in the form of practical experiments.
Sherlock Holmes the Criminal Investigator
Although he claimed to have investigated over five hundred cases in the course of his career, a surprisingly small number (38%) dealt with murder. Fourteen of these resulted in the murderers being arrested or killed, three involved non-human agents, and in all fourteen Holmes made a successful analysis. In five other cases, Holmes succeeded in identifying the criminal but the murderers escaped the reach of the law, and in four other cases Holmes gave the murderers their liberty, because there were extenuating circumstances involved.
Holmes Had an Eye for Detail
Today’s forensic scientist would have found the range of murder cases fascinating. Among the causes of death were gassing, poisoning, asphyxiation, and death from head injuries, comprising a variety of blunt instruments and guns. In the vast majority of these cases, a quick eye for detail at the scene of the crime led Holmes to the murderer with remarkable rapidity. The principles he espoused in the detection of crime are no different today than they were in 1880: the power of observation, the power of deduction, and a wide range of exact knowledge.
Sherlock Holmes a Man Before his Time
In a period when Forensic Science was still in its infancy, Holmes was a man at the top of his league, and this accounts for much of his success as an investigator. He made full use of many of the forensic fields now permanently established: toxicology, ballistics, document examination, even graphology. One of the most useful areas of Forensic Investigation is that of contact traces, which encompasses the principle that an encounter between victim and murderer leads often to small traces of contact, e.g. blood, fibres, hair.
One recalls that one section of the rooms at 221B was devoted to the chemical retort and the microscope especially for this purpose. These days, of course, no one man or woman investigates the causes and effects of a murder. The whole thing is a complex process, involving a variety of experts.
In Holmes’ day, there was no alternative but to become Jack of All Trades. He was sometimes called upon to be police surgeon, forensic analyst, and detective, all at one time. That he did this with such a measure of success places him in a unique position in the annals of crime. In the field of fictional Victorian criminal investigation, Sherlock Holmes remains unique.