It has been suggested that the victims were first strangled before having their throats cut, as that researcher who I believe was Herlock was suggesting that the black blood found in the victim's brain was a direct result of strangulation. I was asked by the researcher to ask Dr Biggs who is a forensic pathologist and has opined many times on the medical evidence in this case and also the Thames torsos for his comments. I have now received his reply and it is set out below
" There are several things that, over the years, have been attributed to strangulation, but more recently have been found to be non-specific (unfortunately!).
So, a protruding tongue was often interpreted as "evidence" of hanging, strangulation, etc. in years gone by, whereas now we wouldn't read too much (if anything) into a protruding tongue. Observations such as injuries (e.g. bruising/scratches) to the neck, together with profuse petechial haemorrhages (i.e. not just a few) above the neck compression level are good when you see them, but they may be subtle (or absent altogether) in cases of genuine strangulation - so a complete absence of neck / facial signs does not exclude strangulation.
As for the "black" blood, it is certainly the case that blood changes its colour depending on the level of oxygenation. Fully oxygenated blood is bright red, whereas it progressively darkens as the oxygen is removed. Deoxygenated blood is, therefore, a very dark red, but it is still red, rather than black. However, in comparison to the "red" colour that might be expected, deoxygenated blood may appear so dark (especially in poor lighting conditions) as to be described as "black" by an observer.
If you were to observe the blood leaving the brain via the veins, it would appear dark red (as the brain has extracted oxygen from it) in comparison to the bright red ("fresh") blood being supplied to it via the arteries. This is a normal finding, and the finding of "black" (i.e. very dark red) blood in the brain would not be a specific indicator of strangulation.
The other snag is, when a person dies the various body tissues don't stop using oxygen - the tissues will continue to extract oxygen from the blood, making it appear dark in colour. So, regardless of whether you are stabbed, strangled or die of natural cause, the blood in a dead body is unlikely to display a bright red colour, and will instead appear dark red / almost black.
If the victim was indeed strangled before being stabbed, this is not something that could be "diagnosed" by a protruding tongue or very dark red blood. She may, of course, still have been strangled, but you would need some other evidence to conclude that safely."
www.trevormarriott.co.uk
" There are several things that, over the years, have been attributed to strangulation, but more recently have been found to be non-specific (unfortunately!).
So, a protruding tongue was often interpreted as "evidence" of hanging, strangulation, etc. in years gone by, whereas now we wouldn't read too much (if anything) into a protruding tongue. Observations such as injuries (e.g. bruising/scratches) to the neck, together with profuse petechial haemorrhages (i.e. not just a few) above the neck compression level are good when you see them, but they may be subtle (or absent altogether) in cases of genuine strangulation - so a complete absence of neck / facial signs does not exclude strangulation.
As for the "black" blood, it is certainly the case that blood changes its colour depending on the level of oxygenation. Fully oxygenated blood is bright red, whereas it progressively darkens as the oxygen is removed. Deoxygenated blood is, therefore, a very dark red, but it is still red, rather than black. However, in comparison to the "red" colour that might be expected, deoxygenated blood may appear so dark (especially in poor lighting conditions) as to be described as "black" by an observer.
If you were to observe the blood leaving the brain via the veins, it would appear dark red (as the brain has extracted oxygen from it) in comparison to the bright red ("fresh") blood being supplied to it via the arteries. This is a normal finding, and the finding of "black" (i.e. very dark red) blood in the brain would not be a specific indicator of strangulation.
The other snag is, when a person dies the various body tissues don't stop using oxygen - the tissues will continue to extract oxygen from the blood, making it appear dark in colour. So, regardless of whether you are stabbed, strangled or die of natural cause, the blood in a dead body is unlikely to display a bright red colour, and will instead appear dark red / almost black.
If the victim was indeed strangled before being stabbed, this is not something that could be "diagnosed" by a protruding tongue or very dark red blood. She may, of course, still have been strangled, but you would need some other evidence to conclude that safely."
www.trevormarriott.co.uk
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