The History of Fingerprinting

Fingerprints have been used and studied in many ways throughout history, although the use has stayed much the same. For example, in ancient Babylon, fingerprints were pressed onto clay tablets in order to deal a deal. Fingerprints have also been found on seals from the Persian Empire.

In 1686, a scientist named Marcello Malpighi discovered ridges, loops, and whorls on fingerprints but did not mention their potential for identification. In 1823 a professor of anatomy (the first to look at fingerprints under s microscope) wrote a thesis containing 9 different types of fingerprints. Still, no mention of identification potential was made.

Around 1858, Sir William Herschel began placing his handprint on the back of contracts, believing that this made it more binding than just a signature. After a while, he bagan requiring palprints, and then just fingerorints. Eventually he noticed that no two fingerprints were the same in his collection. In the 1870s, Dr. Henry Faulds began to study "skin furrows," and passed his thesis on their potential for identifying masses of people to Charles Darwin.

Juan Vucetich, an Argentinian police officer, began the first fingerprinting files (based off the Galton fingerprint patterns) in 1891. The first chemical fingerprint identification was made by him in 1892, on a bloody fingerprint found in a doorframe.

In 1905, the Usited States army began using fingerprints as a mean of personal identification. In 1918, Edward Locard decided and wrote that if two fingerprints matched with at least 12 points of detail, they were the same.

Before computer databases, most fingerprint files were manually searched and maintained, so it took a long time to identify a match.

Lifting Prints

When a fingerprint is found, certain procedures and precautions are taken in order to make sure it is lifted safely and undamaged.

LIFTING FROM A DARK, SOLID SURFACE (such as a lab table)

1. When a fingerprint is suspected to be in an area, lightly dust the spot with white talc powder, then blow on it softly in order to remove excess powder. This action should also reveal where powder is stuck in the ridges of a fingerprint.
2. With a soft brush, brush around the fingerprint until it is relativly isolated from other powdered sections and easily visible.
3. Take clear tape and carefully place it onto the revealed print. When you pull the tape back, talc powder should outline the fingerprint on the tape.
4. Press tape gently onto a black card. Now the fingerprint has been successfully lifted.
   

LIFTING FROM A LIGHT, SOLID SURFACE (such as glass)

1. When a fingerprint is suspected to be in an area, lightly dust the spot with black carbon powder, then blow on it softly in order to remove excess powder. This action should also reveal where powder is stuck in the ridges of a fingerprint.
2. With a soft brush, brush around the fingerprint until it is relativly isolated from other powdered sections and easily visible.
3. Take clear tape and carefully place it onto the revealed print. When you pull the tape back, carbon powder should outline the fingerprint on the tape.
4. Press tape gently onto a white card. Now the fingerprint has been successfully lifted.

Certain chemicals are used to develop prints on other surfaces.

Iodine: Fuming a fingerfrint with iodine vapor will cause a reaction in which the gas is absorbed by the oils of the fingerprint, turning it dark brown or black. Often used on paper.

Cyanoacrylate: Cyanoacrylate is a chemical that makes up about 98% of super glue. When mixed with sodium hydroxide, it will create fumes that react with amino acids in a fingerprint, creating a visible white print.

Silver Nitrate: Silver nitrate reacts with chloride in fingerprints to form silver chloride, which shows up in a reddish-brown hue under ultraviolet light.

Types of Fingerprints

PATTERNS

Fingerprints are classified by arch, loop, or whirl. All three of these types of fingerprints have more specified types. There are eight general prints in total: the Plain Arch, the Tented Arch, the Central Pocket Loop, the Ulnar Loop, the Radial Loop, the Plain Whorl, the Accidental Whorl, and the Double Loop Whorl.

TYPES

Fingerprints at a crime scene fall into three catagories: Plastic, Latent, and Patent.

• Plastic Fingerprints are when a print is left on something and creates an indentation or visible mark. This often happens with wet paint, the gum of envelopes, and substances that can melt from the heat of a hand, such as chocolate.
• Latent Fingerprints are prints that have disappeared to the naked eye as a result of time or some other effect. They can be found by dusting with powder or fuming the area with special types of gasses.
• Patent Fingerprints are prints that have been left because a finger had a foreign substance on it, such as paint, dirt, or blood. They are visible to the naked eye, and thus are usually photographed instead of lifted as is the case of latent prints.

Blood Types

The major types of blood are A, B, AB, and O. A parent has 2 letters in his or her blood type and passes one of them on to a child. Each parent passes on a letter for the blood type, so a parent with an AA type and a parent with a BB type would only have an AB type child.

Transfering blood from one person or storage to another person is called a transfusion. A person can only take blood that works with his or her body. For example, type O can be given to anyone, and people with an O blood type are called Universal Donors. Type AB can take any type of blood into itself, and thus people with an AB type are Universal Recipients. The bodies of people with type A recognize A as ok to be inside it, but type B blood would set the bodies defenses into action. This works the same way with people with type B blood.

"Negative" and "positive" in a blood type refer to whether an RhD antigen exists in a person's blood cells. This is important for transfusions because a person who is negative (lacking RhD) will produce antibodies to combat the RhD on the new blood's cells.

Blood Types Lab

During the blood types lab, I found that the simulated blood took a little while to react with the serums. I had given up on a reaction occuring and moved on to the next step, and when I came back a few minutes later, the serum had caused precipitation!

Here are my results:

History of Handwriting

Before writing, information was passed on orally, and it wasn't written down in any way recognizable as handwriting until the Phoenicians, early Mediterranean traders, whose alphabet was spread across the Eastern Mediterranean area due to their trading industry.

The Greeks adopted and altered the Phoenician alphabet and later the Greek alphabet was became the basis of many other alphabets in Europe. Since it was people of the European origin who colonized North America, the alphabet we use now is based on the Greek alphabet.

Analyzing Handwriting Samples

Handwriting analysis is based on looking for comparisons between two handwriting samples. There are certain indicators and characteristics of certain peoples' writing style.

Twelve general questions are asked when comparing handwriting samples:

• Line quality: do the letters flow or are they written with very intent strokes?
• Spacing of words and letters: what is the average space between words and letters?
• Ration of height, width, and size of letters: are the letters consistent in height, width, and size?
• Connecting strokes: how are capital letter connected to lowercase letters?
• Strokes to begin and end: where do the letters begin and end on the page?
• Unusual letter formation: are any letters written with unusual slants or angles? Are some letters printed rather than written in cursive?
• Pen pressure: how much pressure is applied on upward and downward strokes?
• Slant: do letters slant to the left or right? If the slant is pronounced, a protractor may be used to determine the degree.
• Baseline habits: does the author write on the line or does the writing go above and/or below the line?
• Fancy writing habits: are there any unusual curves and loops or unique styles?
• Placement of diacritics: how does the author cross the t's and dot the i's?
  

This example of handwriting shows several points from the above list:

• The pen pressure is higher towards the bottom of the letters.
• Most repeats of the same letter have a different appearance.
• Many letters are started at the bottom rather than the top.
• The sample shows a very quick, intent style rather than a flowing style.
  

Sadly, since handwriting can be varied by emotions, stress, or even writing implement, handwriting analysis is not a definitive science and is often inaccurate because of how easily handwriting style can be altered.

Hair Analysis

Hair has three parts: the Cuticle, Cortex, and Medulla.

Cuticle: The outer "skin," so to speak, of a strand of hair. It comes in three textures: Coronal, Spinous, and Imbricate.
Cortex: The inside of the hair strand.
Medulla: The inner part of a hair. Humans have a medulla that is much darker that the cortex.