Forensic Science and Deduction

The book emphasizes the use of scientific methods, such as fingerprint analysis, poison detection, and the examination of physical evidence like the coin and plaster casts, to solve the crime, showcasing Thorndyke's logical reasoning.

Thorndyke's methodical approach to the case, including arranging for a postmortem and a verbatim inquest report, exemplifies forensic investigation.

The medical examiner's testimony about the impossibility of self-injection and the nature of the poison demonstrates forensic analysis.

Gray takes wax impressions of the coin as a forensic record, and Inspector Follett reasons about the struggle in the pond based on the items found.

Thorndyke uses deductive reasoning to link the coin to the murder, analyzing the coincidence of the victim's profession and the coin's origin.