It synthesises vitamin D through the action of ultraviolet light on the cholesterol found within its layers.
It also performs excretory functions. Sweat has in it dissolved factions of blood plasma that the body wishes to remove. These include urea, salt and, in dire emergencies, even glucose.
It also, conversely, performs an absorptive role. The uppermost levels of the skin receive very little oxygen from the capillaries. As a result, oxygen from the atmosphere is allowed to diffuse through these levels allowing cellular respiration to continue within them.
It also communicates information to others. The state of our skin allows others to assess our mood, general levels of health, nutrition, infectiousness and our level of self-care, as well as racial origin and reproductive fitness.
Lest you think that your skin is exclusively yours you should know that, in fact, you share it with an astronomical number of other living things. All human skin plays host to a large collection of organisms from all five parts of the taxonomic spectrum. On it can readily be found microscopic examples of animals, plants, fungi, viruses and bacteria. Most are harmless and all are kept in check by each other. As a rough estimate, however, there are probably a thousand or so different species of bacteria alone on the average person’s skin. Unwashed skin may have greater numbers of these micro-organisms but, generally, will not have any extra types.
The precise numbers of these micro-organisms vary greatly depending upon their actual location on the skin. The average number is probably in the region of fifty million or so per square inch. In a sweating, unshaven, unwashed armpit that number could be ten times higher however. In general, though, if all the microbes that could be found on an average human were to be rolled together and placed on a plate the entire volume would probably equal that of a single baked bean, without the tomato sauce.
Any attempt to remove these micro-organisms, however, would be generally pointless, since within a few hours or so recolonisation will have occurred. Some of them could never be removed through washing in any case, because they live virtually within the skin itself.
Daily washing may be seen as part of any animal’s normal grooming patterns. It is not something peculiar to either humans or their cultures. However, the levels to which modern civilisation takes it has nothing to do with health or infection control. It is a social habit that, when looked at carefully, is actually nothing much more than a form of stress control. The fear of social exclusion because of natural body smells is the stuff of nightmares for some. Young boys seem immune to this fear, admittedly, but females and teenagers of either sex appear to be obsessive about ‘cleanliness’. This obsession is all about advertising sexual attractiveness, of course, and nothing to do with cleanliness at all.
An obvious exception to this is when surgery is about to be undertaken; under these circumstances, both the patient and the surgeon should attempt to be as clean as possible simply because pathogen transfer (cross-infection) can so easily occur. This sort of hygiene was only recognised as being useful just before the middle of the 19th century. The idea itself was British, but its earliest practical advocates were Oliver Wendell Holmes, an American doctor and Ignatz Semmelweiss, a Hungarian doctor working in Vienna.
Their recommendations were based entirely upon one easily observable fact; doctors that were made to wash their hands before seeing patients managed to kill less of them. The medical establishment simply dismissed the idea as an insult to their social rank, though, and completely opposed it. Semmelweiss, in particular, was both professionally and socially ostracised for daring to allude to the fact that obstetricians in his hospital were killing their patients because they refused to indulge in any form of hand-washing during working hours.
You might be interested to know that it was an English doctor that finally managed to change everyone’s mind and raise the pursuit of hygiene to that of a medical, ‘best working practice’ (thereby saving millions of lives). He was made a Baronet by Queen Victoria, had one of the most prestigious medical awards named after him, had two statues raised to him, had a hospital named after him, had two stamps issued in his honour, had a mountain in Antarctica named after him and even had an American mouthwash named after him. His name was Joseph Lister and you can still buy the mouthwash – it is called Listerine.
These points about cleanliness are important. As you will see later in the book, the arrogance and stupidity of the medical profession cannot be easily dismissed. When combined with the venal opportunities that modern capitalism in general and the pharmaceutical industry in particular afford, these failings border upon criminal negligence and outright fraud. It is no good relying on government agencies, either. These are not good princes that will take the robber barons to task. These agencies were bought off with corporate gold from the moment of their inception, I am sorry to report.
Chapter Four
Hair Everywhere
We all have hair. Our skin is covered with it. It is one of the major distinguishing features of all mammals, as it happens. Even whales and walruses have it.
The first known animal that definitely had hair was a very early mammalian-type of creature called castorocauda. It looked like a biggish otter and flourished in the middle of the Jurassic Period; this was about the same time as some of the best-known dinosaurs, like the giant swamp-dwelling diplodocus and flying pterodactyls. It was roughly at this point on the evolutionary timeline that feathers also made a first appearance. Both hair and feathers are thought to be genetically derived from the scales of those early dinosaurs.
Human hair actually starts developing in the womb at about fourteen weeks after conception. We do not take much notice of this lanugo hair, as it is called, because it is normally only found on a foetus and thus we never get to see it. Lanugo is replaced by vellus hair at around thirty-four weeks. Babies that still have lanugo are considered to have been born prematurely.
Vellus hair is much finer, softer and has much less colour than lanugo. It is hair proper, though, and can be seen on both sexes, at all ages and on all races (large and distinct variations between them notwithstanding).
In furry animals, this vellus hair quickly develops into normal terminal hair. Fur is, in fact, simply very dense, fine, soft terminal hair. In humans, however, this development into terminal hair is confined to specific and fairly specialised areas like the eyebrows, eyelashes and the top of the head. It is easily distinguishable from vellus because even the finest, least coloured terminal hair is much longer and stronger than any vellus hair.
Strictly speaking, although vellus hair develops into terminal hair at various places around the human body, the process never reverses itself despite what you may read elsewhere. It is true that terminal hair can become vellus-like, but there are differences that always remain between the two. One of the differences, for instance, is that all terminal hair follicles have sebum glands associated with them, whereas with vellus follicles this is not necessarily so.
Hair grows out from these follicles, which are little recesses or pits of infolded skin that reach down in the skin to the lower, dermis layer. At the bottom of these pits are the dermal papillae, which are slightly raised, rounded, bud-like platforms (nipples almost, in fact) of cells rich in blood supply. This is another characteristic difference between vellus and terminal hair. The papilla of a terminal hair has a single loop of a capillary blood vessel within it, whereas those of vellus hair do not. The surface of each little bud is surrounded by the hair bulb, an enlarged portion of the hair shaft found at its base. Hair bulbs receive all their nourishment from the dermal papillae; they do not have their own blood supply.
The hair grows out of the follicles by the continual addition of cells from the hair bulb to the bottom of the shaft. Thus, the shaft is continually pushed upward by the process and the hair is said to ‘grow’.
The blood supply does not extend up the length of the shaft, however, and so the cells rapidly die off after being laid down at the bulb. It is only the hair follicle structure and the hair bulb deep inside it that is actually alive. The filament of hair being pushed out of each follicle is completely dead and is not alive in any sense of the word. So in fact, hair does not ‘grow’ at