Does there exist a reagent that can only be precipitated by Haemoglobin and nothing else?

Question

I recently read Sherlock Holmes and in the book A Study In Scarlet, Holmes says to Watson that he has discovered a reagent that can only be precipitated by Haemoglobin and nothing else. I know about the Guiacum test but is there any other test like I have discussed above as the Sherlock Holmes test.

Answer 1

This very point is well addressed by Laura J Snyder in Sherlock Homes: Scientific Detective (a great read) where the author challenges the view that Conan Doyle is the 'father of scientific crime detection' and argues that the new science of forensics actually influenced Conan Doyles' writing, rather than his novels being the inspiration for the new emerging discipline.

Furthermore, not all his claims were scientifically valid, and the 'infallible test for bloodstains' is a good example.

The relevant passage is as follows:

Let us examine, for example, the ‘infallible’ test for bloodstains Holmes is presented as having ‘invented’. By1887, when A Study in Scarlet was published, many researchers already shared the desire for such a test; this desire was not satisfied until the turn of the 20th century,when the spectroscopic method was developed.

A modern chemist has noted that the method Holmes describes – one which would precipitate a brownish dust and change the color of blood in water to mahogany – would need an acid to increase the oxidation rate, as well as a material to be oxidized. By examining the possibilities for the ‘few white crystals’ and the ‘drop of transparent fluid’ that Holmes uses, this chemist suggests that the ‘Sherlock Holmes test’ would probably have had a sensitivity similar to the guaiacum test that Holmes derides as being ‘clumsy and uncertain’[15].

Moreover, Holmes’ test does not distinguish between human blood and the blood of animals– a problem that, by 1887, was considered an even larger concern than the sensitivity of the blood tests currently in use. A solution to this problem did not arise until the work of Paul Uhlenhuth in 1901 [16].

The two references quoted in the above passage are:

[15] Gerber, S.M. (1983) A study in scarlet: blood identification in 1875. In Chemistry and Crime: From Sherlock Holmes to Today’s Courtroom (Gerber, S.M. ed.), pp. 31–35, American Chemical Society (Columbus,OH, USA)

[16] Thorwald, J. (1965) The Century of the Detective (Winston, R. and Winston, C. trans.), Harcourt, Brace and World