# Differentiating between pig and human blood. **URL:** \ **Category:** Factual Questions\ **Created:** [July 29, 2015, 6:32pm UTC](https://boards.straightdope.com/t/differentiating-between-pig-and-human-blood/726501 "2015-07-29T18:32:41Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Son\_of\_a\_Rich](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/son_of_a_rich/32/5439_2.png) [@Son\_of\_a\_Rich](https://boards.straightdope.com/u/Son_of_a_Rich)\ **Post date:** [July 29, 2015, 6:32pm UTC](https://boards.straightdope.com/t/differentiating-between-pig-and-human-blood/726501/1 "2015-07-29T18:32:41Z")
There’s a bunch of blood at a potential crime scene. Then it’s found to be pig’s blood. How long ago would that scenario have been possible? Were there tests for such a thing in the early to mid 20th century? ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [July 29, 2015, 6:52pm UTC](https://boards.straightdope.com/t/differentiating-between-pig-and-human-blood/726501/2 "2015-07-29T18:52:25Z")
> [@Son\_of\_a\_Rich](#): > > There’s a bunch of blood at a potential crime scene. Then it’s found to be pig’s blood. > How long ago would that scenario have been possible? Were there tests for such a thing in the early to mid 20th century? I suspect the same techniques that allowed doctors to identify human hormones in the 1930s (the “rabbit test”) could identify human blood characteristics and distinguish them from pig blood. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 29, 2015, 10:19pm UTC](https://boards.straightdope.com/t/differentiating-between-pig-and-human-blood/726501/3 "2015-07-29T22:19:25Z")
For what it’s worth, in the first Sherlock Holmes story, Holmes makes a big deal out of just being able to tell the difference between blood (species unspecified) and red paint. ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [July 29, 2015, 11:19pm UTC](https://boards.straightdope.com/t/differentiating-between-pig-and-human-blood/726501/4 "2015-07-29T23:19:19Z")
The precipitin test was developed in 1901: > **[Paul Uhlenhuth](https://en.wikipedia.org/wiki/Paul_Uhlenhuth)** > > Paul Theodor Uhlenhuth (7 January 1870 in Hanover – 13 December 1957 in Freiburg im Breisgau) was a German bacteriologist and immunologist, and Professor at the University of Strasbourg (1911–1918), at the University of Marburg (1918–1923) and at the University of Freiburg (1923–1936). He was a rector of the University of Freiburg from 1928–1929. After his retirement in 1936, he led his own research institute in Freiburg, known as the State Research Laboratory, until his death in 1957. > He is fam... > [@](#): > > He is famous in the annals of forensic science for developing the species precipitin test which could distinguish human blood from animal blood in 1901, a discovery which had tremendous importance in criminal justice in the 20th century. ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [July 30, 2015, 5:02pm UTC](https://boards.straightdope.com/t/differentiating-between-pig-and-human-blood/726501/5 "2015-07-30T17:02:20Z")
> [@Chronos](#): > > For what it’s worth, in the first Sherlock Holmes story, Holmes makes a big deal out of just being able to tell the difference between blood (species unspecified) and red paint. IIRC, he’s excited because he found a reagent that reacts with human blood but no other kind of blood. (evidently pre-figuring Mr. Uhlenhuth’s real-world discovery). Obviously very significant for a detective, particularly in an age when more people were involved in killing chickens or other activities that could lead to plausibly claiming a blood stain is not from human blood. ---
**Author:** ![chrisk](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@chrisk](https://boards.straightdope.com/u/chrisk)\ **Post date:** [July 30, 2015, 5:35pm UTC](https://boards.straightdope.com/t/differentiating-between-pig-and-human-blood/726501/6 "2015-07-30T17:35:32Z")
> [@Quercus](#): > > IIRC, he’s excited because he found a reagent that reacts with human blood but no other kind of blood. (evidently pre-figuring Mr. Uhlenhuth’s real-world discovery). Obviously very significant for a detective, particularly in an age when more people were involved in killing chickens or other activities that could lead to plausibly claiming a blood stain is not from human blood. Well, the reagent mentioned in “A Study in Scarlet” was for hemoglobin, (though Doyle seems to have misspelled it even according to the usage at the time!) and he makes no mention of being able to differentiate human blood from animal, just old bloodstains versus red mud/fruit/rust or whatever. There may well be a different, more specific reagent mentioned in a different book or story. Holmes would certainly have found the distinction between human and animal blood a forensically important one. ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [July 30, 2015, 7:39pm UTC](https://boards.straightdope.com/t/differentiating-between-pig-and-human-blood/726501/7 "2015-07-30T19:39:57Z")
> [@chrisk](#): > > Well, the reagent mentioned in “A Study in Scarlet” was for hemoglobin, (though Doyle seems to have misspelled it even according to the usage at the time!) and he makes no mention of being able to differentiate human blood from animal, just old bloodstains versus red mud/fruit/rust or whatever. > > There may well be a different, more specific reagent mentioned in a different book or story. Holmes would certainly have found the distinction between human and animal blood a forensically important one. Hmm. Evidently, I did Not Recall Correctly. Unless there’s somewhere else… my memory is Holmes explaining to Watson why a test for specifically human blood would be useful, in case a suspect claims the blood on his sleeve is from an animal. But at this point, I wouldn’t bet too much on my memory, when Google says otherwise. ---
**Author:** ![kaylasdad99](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kaylasdad99/32/3398_2.png) [@kaylasdad99](https://boards.straightdope.com/u/kaylasdad99)\ **Post date:** [July 30, 2015, 8:09pm UTC](https://boards.straightdope.com/t/differentiating-between-pig-and-human-blood/726501/8 "2015-07-30T20:09:14Z")
Pour a bucket of it over an emotionally unstable psychokinetic chick in a prom dress. If the town is still standing when she calms down, it was probably human blood.