Obtain at least half a dozen specimens from different areas of your scalp and label each with the source crown, side, front, back, etc. Procedure This lab has three parts. Evidence of probate of a will comes in the form of a judgment or order for probate and documents called Letters Testamentary. Ovoid bodies are more commonly found in cattle, dog, and other non-human hair, but are sometimes found in human hair. Because hair grows out of the skin, chemicals that the skin absorbs can become incorporated into hair.
Hairs matching those of his dog also were found. Ingested or absorbed toxins such as arsenic, lead, and drugs can be detected by chemical analysis of hair. Q3: What is the primary consideration in choosing a mounting fluid for a hair specimen, and why? Microscopic Examination Microscopic examination consists of observing specimens with a compound or comparison microscope at medium to high magnification typically, 100X to 400X or more to note fine structural details. You'll have to double check that though. Still, evidence with class characteristics can be useful.
The length and the shape of a hair can be used to identify the place on the body from which it originated Innes, 2000 Sites of origin are considered to be the scalp, eyebrow , beard, underarm, body and pubic region Lane, 1992 Some researchers also include ear hair as a separate region of origin Crocker,1999. Note the appearance of the distal end tip as tapered natural or razor-cut , scissors- or clipper-cut square or angled , split, frayed, abraded, crushed, broken, or otherwise. If scale detail is visible at high magnification, note the appearance of the scales. This is known as Locard's exchange principle. Testing for Substances in the Hair Shaft a.
. No two pairs of shoes or sets of car tires wear in exactly the same way. Cortex Note the texture of the cortex as coarse, medium, or fine. If the cuticle is present, note the appearance of the outer cuticle margin exterior surface of the hair as flat, smooth, cracked, or serrated. If the sample contains particular chemicals, it will absors some of the light and then reemit light of a different color. This method allows the investigator to collect the evidence at the bottom of the bag rather than have it disperse into the air Bisbing, 2001.
Impression evidence such as marks left on a fired bullet, shoeprints, tire tracks, and toolmarks may be unique and therefore have individual characteristics. A single piece of class evidence rarely can be used to convict someone, but it can be and often is used to exonerate someone. For a permanent or semi-permanent wet mount, use Permount, Canada balsam, Melt Mount, or a similar mounting fluid. The Function of Hair a. In homicide and sexual assault cases, physical evidence is the number one determinant of guilt or innocence. The center of the hair is called the medulla.
Such glass fragments may remain at the scene for a long time depending on the type of crime and do not degrade like biological evidence. There is also the evidence that Allied soldiers found when they liberated the camps. The shoe printmay also be individual evidence due to the fact that not everyonewalks the same. Capable of being but not yet in existence evidence. In a fluorescence microscope, a beam of light of a certain color is used. You can use distilled water, glycerol glycerin , castor oil, or clove oil to make a temporary wet mount.
This will result in no new hair growth in the transplanted area whatsoever. Ends Note the presence or absence of a root on the proximal end. Fracture or tear patterns can be individualizing; the way glass breaks, paper tears, and cloth rips is unique in each situation. The system utilizes a standard laboratory microscope with phase-contrast optics and a Mettler hot stage for temperature control. This text includes numerous microscopic studies of hairs from many animals. It is also used to decrease friction, to protect against sunlight, and to act as a sense organ.
Another risk is that of an unnatural look developing with a pattern on the hair that is patchy. Jury instructions define the elements of the charged offense and define the burden of proof. He has been serving the forensic community for 27 years. The type of handgun with which a victim is shot is a class characteristic. This type of evidence has numerous points of comparison.
Testing the Hair Follicle a. You can use your compound microscope at its lowest magnification, usually 20X or 40X. Class characteristic - properties of evidence that can only be associated with a group and not a single source. The way I see it, evidence must be described in the most simple way or in the most plain language possible. Note its appearance as opaque, translucent, amorphous, or cellular. Tweezers can also crush the delicate root structure and surrounding tissue which is used in D.