Human versus Animal Blood

augusta · Post by **augusta** » Mon Jun 23, 2008 10:59 pm

Tonite (June 23) I was watching TruTV at 11:30 pm. They had a case on there about a mail order bride who had an affair with the gardener and was murdered.

I caught an interesting sentence. The cops found some blood (I was on my laptop at the same time and didn't catch what the blood was found on). They said they were unable to determine whether it was human blood or animal blood.

Now when the Bordens were murdered in 1892, it was claimed that they could distinguish animal blood from human blood. It was something to do with the size of part of the blood, I think.

What circumstances would there have to be for them to NOT be able to tell if it was human or animal blood?

Could they really tell the difference in 1892? Or was it shown later that they really couldn't tell the difference?

How do they tell the difference now? (I imagine it's a lot more scientific than how they did it in 1892.)

Harry · Post by **Harry** » Mon Jun 23, 2008 11:20 pm

Don't know how its done now but here's Prof. Wood's Prelim testimony (p375+)

Q. Are you prepared to say, Professor, in the test for dried blood, one can assert with positiveness that a given specimen is, or is not, human blood?
A. You can state whether it is consistent with its being human blood, or not. You cannot state positively that it is.
Q. Science has not proceeded far enough yet so you can say whether it is, or not, human blood?
A. No; but you can say it is not certain animals blood.
Q. When you get into the class of mammals that suckle their young, after blood has been dried, the test is not so satisfactory?
A. You can tell between those, certain ones.
Q. Between a man and a dog it is pretty close?
A. That is very close.
Q. Between a man and a horse it is a little further off?
A. Yes Sir. The principal ones, however, are the opossum and seal, and one kind of guinea pig; those are the nearest human, nearer than the dog.
Q. The dog is sufficiently near so to make it somewhat doubtful?
A. It is a little more definite in the case of a dog nowadays than it used to be.
Q. A little more than it used to be?
A. Yes Sir.
(Mr. Knowlton) The difference is a little more obvious you mean?
A. We detect it more easily now than we used to."

He states essentially the same thing at the trial (p1005) and adds:

"...That I examined and found it to be a blood stain, and the blood corpuscles when examined with a high power of the microscope averaged in measurement 1-3243 of an inch. That is the average measurement within the limits of human blood, and it is therefore consistent with its being a human blood stain."

Kat · Post by **Kat** » Tue Jun 24, 2008 2:38 am

Thanks again for more informative testimony, Har!

Augusta, how can that be that now-a-days they couldn't tell the difference? The only thing I can think of is the sample was small and too old or degraded?
I've not heard of such a thing this century.
Wish there was a more complete description of the context of the exchange.

snokkums · Post by **snokkums** » Tue Jun 24, 2008 5:31 am

Now they can tell pretty much if it animal or human unless it's contamianted with other stuff, like the elements got to it (such as dirt or mud, and there is more mud than blood).

Shelley · Post by **Shelley** » Tue Jun 24, 2008 9:18 am

There's quite a lot of info on the internet on this topic with serologists using chromosone counts, DNA and other methods of determining species. Yes, how I wish Harvard still had all the paperwork on tests run at the medical school for this case. I have tried several times to find descendants of Dr. Wood, and have called Harvard hoping copies of the lab findings might still be in the archives- all to no avail.

augusta · Post by **augusta** » Sat Jun 28, 2008 4:24 pm

Thanks for posting the testimony, Harry! Seems like I remember also that Wood or Draper testified about the size of the corpuscles (or something akin to it). I think that was one way they could tell the difference then. It was very interesting to read - or re-read - the testimony you posted.

Kat - I know! I musta missed something before they said that on that show, but they said nothing afterward. It can't be that, using a normal blood sample, they cannot tell animal from man today.

There must have been something wrong with the sample, as Snookums says. Unless the sample was too small. I've heard that happening many times - before today's sophisticated DNA testing was created. A lot of times the lab tech would store a too-small sample in the freezer, then when these advanced DNA techniques came along the frozen sample will be tested and compared to all those incarcerated whose DNA is in a huge database.