This story is not only surprisingly charming to the reader but also unexpectedly relevant to the contemporary fad for forensic procedurals. Thorndyke seems, in many ways, to having been designed to be an interesting not quite anti-Holmes. Thorndyke does not call into question the necessity for the careful checking of clues and scientific examination of all possible aspects of the crime. What he calls into question is what might called the fetishization of particular forms of scientific findings without considering all the possibilities of how that “evidence” came to be found at the scene of the crime. In this case, Thorndyke, in defending Reuben Hornby, has to counter the automatic assumption of the police that “a finger-print as a kind of magical touchstone, a final proof, beyond which inquiry need not go.” Indeed, Thorndyke argues that “this is an entire mistake. A finger-print is merely a fact, a very important and significant one, I admit, but still a fact, which, like any other fact, requires to be weighed and measured with reference to its evidential value.”
Thorndyke does not debunk the science behind fingerprinting nor is he skeptical of the process of scientific investigation. What he does present is the difference between true scientific inquiry and the automatic assumption that having mastered a particular scientific technique one may fall back upon it as if it were written in stone. And indeed, he demonstrates that any technique of investigation will soon be countered by criminals who take it into account and counter it with new techniques of their own. It is particularly interesting to read this book today at a time when many treat DNA evidence with reverence but without real understandings of its strengths and weaknesses. Indeed one wonders what opinions Dr. Thorndyke would have as to the reliability of many of today’s labs and many of today’s experts.
For those who are interested in the details of forensic analysis Freeman devotes a good part of the book to that very aspect of forensics which is most overlooked in most television procedurals; how does one present evidence in a way that is understandable and convincing to juries. For those who are less interested in the scientific aspect of “ratiocination” Freeman includes a wonderful analysis of the Holmesian deductive method as Thorndyke explains not only why his supposition that a figure outside the window was a stationmaster was sound but also why it was, for all that soundness, a mere educated guess.
In conclusion: This is an enjoyably written book which avoids unneeded plot complications, does a good job of introducing the reader to Dr. Thorndyke and his methods and may do well to assuage that empty feeling the reader is left with after consuming the last of the Holmes stories.