All That Remains: A Renowned Forensic Scientist on Death, Mortality, and Solving Crimes

by Sue Black

Death and the hyped-up circus that surrounds her are perhaps more laden with clichés than almost any other aspect of human existence.

despite being feminine in many languages where nouns have genders (including Latin, French, Spanish, Italian, Polish, Lithuanian and Norse), she is often none the less depicted as a man.

I didn’t ‘lose’ my father – I know exactly where he is. He is buried at the top of Tomnahurich Cemetery in Inverness, in a lovely wooden box provided by Bill Fraser, the family funeral director, of which he might have approved, although he would probably have thought it too expensive.

As Fiona, our inspirational chaplain at Dundee University, puts it so eloquently, there is no comfort to be had from soft words spoken at a safe distance.

Forensic pathology seeks evidence of a cause and manner of death – the end of the journey – whereas forensic anthropology reconstructs the life led, the journey itself, across the full span of its duration.

In these days of ever-expanding scientific knowledge, pathologists cannot be expected to be experts in everything, and the anthropologist has an important role to play in the investigation of serious crimes involving a death. Forensic anthropologists assist in unravelling the clues associated with the identity of the victim and may aid the pathologist to reach his or her final decisions about the manner and cause of death.

From the point of view of the forensic anthropologist, a long life is good news, as the longer it has been, the more scars of experience will be written and stored within the body, and the clearer their imprint on our mortal remains will be.

Over the centuries, society has catalogued and measured life expectancy, by which we mean the age at which we are statistically most likely to die – or, to look at it more positively, the length of time we are likely to spend living.

In 1930, the year of my mother’s birth, female life expectancy was sixty-three, so on her death at seventy-seven she exceeded the norm by fourteen years. My grandmother fared even better: when she was born, in 1898, her life expectancy would have been only fifty-two. She lived to be seventy-eight, outstripping that by twenty-six years, which may in part be a reflection of the huge number of medical advances during her lifetime – although her cigarettes didn’t help her in the end. The prediction for me, when I arrived in 1961, was a life that might be seventy-four years long. That would leave me now with just seventeen to go. My goodness me, how did that happen so quickly? However, based on my current age and lifestyle, I can now realistically expect to reach eighty-five, and I may have another twenty-nine years or more to look forward to. Phew.

the maximum age to which our species is capable of living is not increasing. What is changing dramatically is the average age at which we die, and therefore we are seeing an increase in the number of individuals falling into the far right regions of the bell curve. In other words, we are changing the shape of human demography.

If you cut into the cadaver and noticed it starting to bleed with bright red arterial blood, I was warned, just remember that cadavers don’t bleed. What you will have cut is your own finger. The scalpel blades are so sharp and the room so cold that you don’t feel them slicing into your skin.

It is no coincidence that most students begin dissection with the thorax. The breastbone is so close to the skin that no matter how hard you try, there is little you can do wrong. You simply cannot go too deep.

The yellow fat appears and as this comes into contact with your warmer hands it liquefies. Holding the scalpel and forceps suddenly becomes tricky and the flicker of confidence you had a few moments earlier evaporates as the forceps slip off the skin and fat and fluid splash up into your face. Nobody has warned you about this. Formalin smells nasty but it tastes worse. You only ever make that mistake once.

The study of anatomy polarises its students: they either love it or they hate it. The fascination lies in the logic and order of the subject; the downside is the vast amount of information to be learned – that and the smell of formalin.

As recently as 1998, the sculptor Anthony-Noel Kelly was jailed for stealing body parts from the Royal College of Surgeons in a case that cast a spotlight on the ethics of art and the legal status of human remains donated to medical science. And in 2005, an American medical tissue company was closed down after its president was convicted of illegally harvesting body parts and selling them on to medical organisations.

Given that the sale of human remains is legal in many countries and that a good number of institutions around the world will pay a hefty price even for an articulated human skeleton, perhaps it should not surprise us that the ancient crime of grave-robbing persists in modern-day forms.

After Lord Nelson’s death in the Battle of Trafalgar in 1805, his body was stored in a vat of ‘spirit of wine’ (brandy and ethanol) for his journey home to a hero’s funeral.

Formaldehyde is a disinfectant, a biocide and a tissue fixative and works so well that its aqueous solution, formalin, is still the most commonly used preservative worldwide.

In the 1970s, the anatomist Gunther von Hagens pioneered plastination, whereby water and fat are removed under vacuum and replaced by polymers. These body parts have eternal life. As they will never decompose, we have succeeded in designing a new environmental pollutant.

The cause of death given for a cadaver often elicits concern in our students when, on coming to examine the organ in question, they find no disease or abnormality. When death is due simply to old age and it is known that the deceased desired to bequeath their body, the recorded cause of death will inevitably be reasoned and educated supposition.

Researchers believe that a sense of identity is a manifestation and extension of the maturation of the concept of self which allows us to develop an intimate and intricate society. It enables us, to a certain degree, to express individuality, and perhaps helps others to tolerate it, by permitting us to both promote and display who we are, who we want to be and what we choose to stand for.

The importance of identity in our society, and the fact that it can be manipulated, places it at the core of investigative sciences, including my world of forensic anthropology – the identification of the human, or what remains of the human, for medico-legal purposes.

Forensic anthropologists look to features of our corporeal biology or chemistry to analyse a trackable and readable history of the life lived, and to confirm whether the evidence recovered matches traces left by that person in the past. In other words, we search for clues of the narrative written in our bodies, innate and acquired, laid down between birth and death.

Death may be a single event for the individual but it is a process for the body’s cells, and to understand how that works, we must be familiar with the life cycle of the building blocks of the organism.

Every human is created when two separate cells fuse and then begin to multiply – an incredibly humble beginning from an unimpressive little sack of proteins. After forty weeks in utero, those two cells will have gone through the most miraculous transformation, becoming a highly organised mass of over 26 billion.

By the time that baby becomes an adult, the cell mass will have expanded to over 50 trillion, grouped into some 250 different cell types forming four basic tissues – epithelial, connective, muscular and nervous – and a variety of sub-tissues.

Remarkably, only five organs are considered vital to sustained life: the heart, brain, lungs, kidneys and liver.

Each cell, tissue type and organ has its own life expectancy, which is managed like stock turnover in a supermarket based on a ‘best before’ date. Somewhat ironically, those with the shortest shelf life are the ones that start it all off: sperm survive for only three to five days after formation.

The liver takes a full year to replace all its cells and the skeleton almost fifteen years.

It does, though, raise a question: just how much alteration can a biological entity sustain while remaining recognisable as the same individual and maintaining its traceable identity?

There are at least four cell types in our bodies that are never replaced and which can live to be as old as we are – technically even longer, in the case of those formed before we are born.

The four permanent cell types are the neurons in our nervous system, a tiny little area of bone at the base of our skull called the otic capsule, the enamel in our teeth and the lenses in our eyes.

Our neurons, or nerve cells, are formed in the very early months of embryonic development and by the time we are born we will have as many as we are going to have for the rest of our lives.

The longest are those that transmit pain and other sensations along the full length of the body, from the tip of the little toe, all the way up through the foot, leg and thigh, up the spine and the brain stem and on to the sensory cortex of the brain at the top of the head. If you are six feet tall, each single neuron on that pathway may be close to seven feet long.

with the help of a fluorescent protein we can now see a memory being formed at the single synapse level. Practical application may yet be a little too much science fiction for us to embrace fully, although I am tempted to predict that an understanding of the key role neurons may play in establishing identity might not be so very far away.

the otic capsule, situated in the very depths of the skull around the inner ear. This is part of the petrous temporal bone, which houses the cochlea, the organ of hearing, and the semi-circular canals responsible for balance. As the inner ear forms in the embryo and fetus, it does so to full adult size immediately and remains insulated against growth and remodelling through the production of high levels of osteoprotegerin (OPG), a basic glycoprotein that suppresses bone turnover.

Even though the otic region is already adult-sized in newborn babies, it is very, very small, representing, in volumetric terms, only around 200 microlitres – about the size of four raindrops.

At its most basic level, every cell in our body is comprised of chemicals. Their formation, survival and replication are dependent on a supply of elemental building blocks, an energy source to bind them together and keep them alive and a waste-disposal outlet for their by-products.

the core components of every single cell, tissue and organ can be obtained only from what we ingest. We are, literally, what we eat.

While it is a fallacy that a pregnant woman eats for two, she does need to ensure that her diet is sufficient to meet not only her own needs but also those of a very demanding passenger.

within our head, in that minute piece of bone just big enough to hold four raindrops, we will perhaps carry for the rest of our lives the elemental signature of what our mother had for lunch when she was four months pregnant.

As water percolates through various geological formations, it will take up isotope ratios of elements specific to that location and when we ingest it, its signature will be transferred into the chemical make-up of all our tissues.

The crowns of all our deciduous teeth (milk or baby teeth) are formed before we are born and their composition is therefore also directly associated with maternal diet, as is that of the crown of our first adult molar.

hair and nails are rich sources of information about diet as their structure is laid down in a linear fashion and they grow at a relatively regular rate. They provide a potential chemical timeline for the deposition of metabolised ingested nutrients that can be read almost like a barcode.

Stable isotope analysis is a good example of one of the scientific techniques that can assist us.

The ratio of carbon- and nitrogen-stable isotopes in our tissues may tell us something about diet: whether a person was a carnivore, a pescatarian or a vegetarian. The oxygen isotope ratios may reveal more about the source of water in the diet, and from the stable isotope signature associated with water, we may be able to deduce where they have been living.

Analysis of hair and nails can produce a sequential timeline for geographical relocation. This can be extremely useful in trying to identify an unknown deceased person, or to track the movements of criminals.

Hair analysis can also tell us about persistent consumption of a variety of substances, including drugs such as heroin, cocaine and methamphetamine.

So we could, in theory, look at the remains of an individual and, from the isotopic signatures in the otic capsule and first molar, discover where in the world their mother was living when she was pregnant with them and the nature of her diet. We could then analyse the remainder of the adult teeth to establish where the deceased person had grown up, and then the rest of their bones to determine where they had lived for the past fifteen years or so. Finally, we could use their hair and nails to locate where they spent the last years or months of their life.

Our bodies change not only throughout our life, but also in death. As the processes associated with organismal and cellular deconstruction begin, so we start to break down into the chemical components that were used to build us in the first place.