Found in the endless Haining archive, an article cut from The Union Jack Detective Supplement, undated but about 1925. Peter Haining was a collector of Sexton Blake books so this piece on the scientific / forensic detective Professor Alexandre Lacassagne (1843-1924) would have interested him.
A Real Sexton Blake
By Donald Campbell.
They read like improbabilities, the achievements of this real-life Sexton Blake. But we credit them when we see the working methods of Professor Lacassagne, who has recently died.
A few weeks ago there died at Lyons one of the greatest scientists of his own kind in the world.
This was Professor Alexandre Lacassagne, honorary professor to the Faculty of Medicine, who passed away at the ripe old age of eighty-two. He was the first man in Europe to apply science to detective work. He served as an officer in the army of Napoleon III., and fought through the Franco-Prussian War of 1870-71.He was taken prisoner. When released he was attached to the Bataillons d’Afrique, then a species of depot for all the rough characters who came to do their military service, usually very much against their wills.
First he merely studied characters, but afterwards the real criminals, and specialized offenders who came under his treatment.