Originally posted by JeffHamm
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Hi Steve,
Nice. This got me thinking and I was wondering if we might be able to tailor the above more specifically to the Nichols' case.
Nichols was a bit smaller compared to the average female today (she was only 5' 2" tall, and apparently the average height for adult females in the UK today is 5'4"). Also, the average person will include males, who tend to be larger.
I did a quick search to see if there was any way to convert a person's weight to an estimate of blood volume. Apparently, according to Wikipedia, the source of all truth and knowledge, "The blood volume is 70 ml/kg body weight in adult males, 65 ml/kg in adult females and 70-75 ml/kg in children (1 year old and over)."
So I thought I would grab Nichols' weight from her description on the Victim's page, but (and there's always a but) unfortunately, I can't find any record of her weight, only her height (5' 2"). So next I went looking at a way to estimate weight based upon height.
That led me to this though, which lists ranges for weight for women of various heights presuming a healthy BMI. It could be argued that Nichols might, due to her poverty, be below a healthy BMI, and she is described on the victim's page as having "small delicate features", but I've got with these values to be conservative. The table would suggest a weight between 104 and 131lbs, or 47 to 59.5 kg. That page also provides a link to height-weight ranges for under weight, overweight, and obese ranges too.
I stuck with a healthy range to start, and that would suggest that her blood volume is likely to have been much less than the 5000ml average, and would likely be in the range of 3073 ml to 3870 ml.
And using the low medium and high rates of blood loss you mentioned, those give us 50% loss times of (when the heart stops beating, so no more loss under pressure):
.........................slow........med........fa st
104lbs (47kg) .. 2m 29s | 2m 04s | 1m 46s
131lbs (59.5kg) 3m 07s | 2m 36s | 2m 14s
all of which are under 3 minutes, apart from the 3m 7s for slow rate and upper end of the chosen weights.
Obviously, if she was lighter than I've included the times get shorter, and if she was heavier they would get longer.
The "overweight" range on the table is listed as 136 to 158 lbs (61.8-71.8kgs), and doing the same thing with those we are still under 4 minutes to reach the 50% blood loss even under the well over weight and slow rate of loss.
.........................slow........med........fa st
136lbs (61.8kg) 3m 15s | 2m 42s | 2m 19s
158lbs (71.8kg) 3m 46s | 3m 08s | 2m 41s
As a result, it is rather improbable that any of the police saw "bleeding under pressure", and any bleeding would be passive flow. We know it's going to take between 3 and 4 minutes for the carmen to reach Mizen, and he in turn will require another 3-4 minutes to get to the crime scene, so at the very least we're talking 6 minutes, in which case we're well beyond any of these times. Given PC Neil seems to arrive about the time the carmen reach PC Mizen, and their journey looks to require over 3 minutes, that means PC Neil appears to arrive between 3 & 4 minutes after the carmen left (and of course, she's also bleeding the whole time Cross/Lechmere has to wait for Paul to come up, then for them to examine her, etc), which just makes it even less and less probable that she would be bleeding under pressure by the time PC Neil arrives, let alone Mizen.
Now, if JtR was interrupted by Cross/Lechmere entering Buck's Row, it would take him roughly 1m 30s to get to the crime scene, but he waits for Paul, who has to walk another 120 feet, so another 25seconds. The murder, starting at the point of the first throat cut, probably only required a couple minutes, let's say 2 since all he has to do is cut the throat twice, lift the dress, and make a number of stabs and cuts. Maybe 2 minutes is overly generous and I should say 1 to avoid cherry picking. So from the time of the first throat cut in this situation, she's been bleeding under pressure for something like 2m 55s by the time the carmen reach her body.
As such, under those circumstances, there is the slightest possibility that Paul could have detected the last signs of life, although that tends to require her to be near the upper end of the healthy weight and to have bled on the slow end of the range. Given her wounds, and her life style, I'm thinking that's a hard position to defend, but it is there to consider.
Anyway, I think there's some useful information here that can be used. Obviously, there are assumptions one has to make, but by working with the upper and lower limits (the margins of error introduced due to our having to make assumptions), I think we can still use that to guide our understanding.
- Jeff
Nice examples of body weight v Blood volume.
I would tend to suggest she was larger than you think BMI wise, she is described as being well built, some even suggest stout.
Sadly as you have found we have no real data.
Therefore you assumptions are a valid range.
Your post takes mine a step further, adding to the arguments against either officer seeing Bleeding under pressure.
Very Good and informative post.
Steve
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