Syrotuck uses the word “scent” to refer to the combination of odors or smells that characterize an individual; he uses the word “odor” to refer to specific sources of odors such as foot odors and chemical odors

Dr J Amoore has broken odors down into 7 categories, which differed in the shape of their molecular structures.

Dr. R. Wright has suggested that the 2 broad categories of how receptor cells in the nose are stimulated are (1) by vibration or (2) by the chemical shape of vapors and gases.

The source of human scent is the body.

Genetics determines our hormone balance and as a result, our emotional responses.

Scent-wise all human beings smell the same.

Of interest to people working with dogs is the fact that the size and function of the sweat glands of Caucasians and Orientals are all different.

Cultural customs and diet will all have an effect on odors given off in body secretions.

The human body is made up of approximately 60 trillion cells.

In humans, approximately 50 million cells die every second and some are shed from our body.

Syrotuck’s main focus in the book is on the skin cells that are shed from the human body.

Dead skin cells that are shed from our bodies are called boats.

Dead skin cells are never visible to the naked eye.

Sweat is one of the primary body odors.

Environment has no effect on sweat.

The composition of sweat is the same in every individual.

The 2 sources of sweat are the eccrine and apocrine glands.

Eccrine glands cover the entire body.

Two of the areas that contain the most eccrine glands are the soles of the feet and the forehead.

Cold is the main stimulus for the eccrine gland.

The apocrine glands are located at the base of hair follicles in areas like the perianus and the genitals.

Stress is the main stimulus for the apocrine sweat gland.

The offensive odor of sweat is produced when apocrine sweat is exposed to bacteria on the skin.

Sebaceous glands are found on the face, scalp and pubic area.

The respiratory and genitourinary tracts contribute to odor.

Research has shown that regular bathing may increase bacterial activity on the skin because the act of washing away the skin exposes hidden microorganisms.

The body’s exposure to the environment means that bacteria, fungi and parasites end up inhabiting the skin.

The face, neck, armpits and groin have a high density of bacteria.

It may be true that there is almost as much bacteria on the skin as there is in the soil.

The main ingredients of human scent are bacteria acting on dead skin cells.

When dead skin cells are broken down by the action of bacteria, the process is called putrafaction.  Putrafaction gives off odors in the form of vapors and gases.

A single bacterium has a long life span – it grows, matures, reproduces and dies over a period of weeks.

Temperature is probably the most significant factor that affects the growth of bacteria.

Loose clothing and exposed skin will increase the escape of scent from a warm body better than clothing that is tighter fitting.

Any type of rubber or plastic clothing that increases overheating and sweating can give off as much scent as if the person were not wearing such clothing.

Any type of rubber or plastic clothing that increases overheating and sweating can give off as much scent as if the person were not wearing such clothing.

One researcher claims that a dog can detect the scent of a person’s foot approximately 8 minutes after being in a new pair of rubber boots 0.2 millimeters thick.

Body odor is produced because bacteria acts upon our body’s dead skin cells, residues and body secretions.

Regarding soaps, laundry preparations and clothing, all individuals react the same way and give off the same odors to these items.

A person’s emotions will have no effect on the odor they give off.

Rafts are cornflake in shape, which makes them aerodynamic.

About 10 cells are shed every minute by the body.

Rafts have nothing to do with the odor that comes off of a person’s body.

Rafts form a kind of vapor cloud around each person.

The size of the raft will determine how far away it will be carried.

Another name for raft is dead skin cell.

There is no theory that supports the idea that a current of air next to the surface of the skin acts as a transport system for rafts.

Air seems to flow from the feet upward to the top of the head.

The flow of air increases as the outside temperature increases.

It seems apparent that body air currents provide a transportation system for the body’s dead skin cells (rafts) that are laden with bacteria.

The individual scent of each person is the human bacteria working on the dead skin cells.

From a chemical and molecular view point, there are an infinite number of individual odors that can be created.

When rafts are cast into the environment they are affected by wind, temperature and humidity.

One of the best ways to judge wind conditions is to moisten a finger and hold it in the air.

A good way to assess wind conditions is to watch smoke that has been generated at ground level.

Temperature varies as one goes from ground level to farther distances off the ground.

A cross wind will have no effect on rafts.

Although wind may be coming from one particular direction, a roadway will tend to channel air and scent along its length.

Scent may pool in basin-like pockets when cool air is flowing downhill.

When there is little air exchange, it tends to be a dead area with regard to scent.

Temperature and humidity have little effect on the dispersion of rafts.

If a dog handler is using air currents in a search effort, he will find that wind currents will travel up a slope in the morning.

As the sun starts to lower, the ridges and upper air cool first and the cool air will run down the slope.

When working dogs on scent, it is best to work the ridges in the morning and the valleys in the later part of the afternoon.

At night, air in closed areas cools first and flows uphill.

At night, cool air tends to be slower moving and subject to less turbulence.

Exposed surfaces are exposed to greater extremes of temperature.

Light surfaces absorb heat and may cause small areas of counter-currents.

Less heat tends to occur on small rocky outcrops and creates substantial counter-currents.

All humans have the same scent.

All humans have the same scent.

Syrotuck proposes that each human is surrounded by a cloud of scent, portions of which drop off and settle on the ground around him.

Sight is the best developed sense in newborn babies.

A lot of what we know about scent comes from studies of humans.

A lot of what we know about scent comes from studies of humans.

Blind people have a less developed sense of smell than sighted people.

Many four footed animals, including dogs have a keen sense of smell.

Discrimination is the ability of a dog to find one particular smell among numerous other odors.

There have been no studies that show that the more training humans and animals receive, the better their ability to discriminate among odors.

Sometimes the presence of certain chemicals blocks the ability to smell other odors.

Studies show that if a human first sniffs the odor of acetone and then the odor of xylene, he/she will be able to discern the odor of xylene; but if the odor of xylene is sniffed first followed by the acetone odor, the acetone smell will not be discernable. This might be applicable to dogs.

Gasoline will not block a dog’s sense of smell.

It is likely that a dog will become very disturbed by a strong new smell.

Since a dog’s scenting ability is so developed it is not really necessary to expose him to a lot of new environments and odors.

Certain odors like a female in season evoke predictable responses in a dog. This same principle may explain why a dog may respond with dislike to a person who is afraid of him.

Receptor sites in the nose are involved in human and animal scenting.

Gases and vapors are not involved in giving off odors.

All odors must reach the nose.All odors must reach the nose.

Vaporous material will not retain odor for a very long time.

The warmer something is the more odiferous it becomes.

Anything frozen will never give off an odor.

Finding a cold body in a cold environment will be difficult.

Humans can smell all the same things that dogs can.

Some slightly porous materials can hold vaporous odors for many hours.

All breeds of dogs have the same scenting abilities.

The sinuses of a dog are probably involved with scenting ability.

If a dog has infected teeth, it may seriously affect his ability to use his nose.

Once the mucous membranes of a dog are damaged, the nose lining will never regenerate.

Almost one eighth of the dog’s brain is involved with olfaction.

Most albino animals have an especially keen sense of smell.

It is necessary to keep breeding for rich brown pigment in the olfactory areas of working dogs since it is associated with the ability to smell.

Anosmia means an inability to smell.

The more olfactory cells in a human or animal, the better the sense of smell.

The size of various dog breeds has nothing to do with how many olfactory cells it has.

Dachshunds have more olfactory cells than Fox Terriers.

A dog’s sense of smell is about 44 times greater than a human’s sense of smell.

Some researchers feel that the larger the olfactory area of an animal, the better will be its ability to discriminate among different odors.

Short nosed (brachycephalic) dogs have the best senses of smell.

Certain breeds of white or light colored dogs may have an impaired sense of smell.

Dogs with smaller sized brains have a reduced olfactory area and may  have a less keen sense of smell than larger dogs.

There is little doubt that regular practice will improve both the working ability of the dog's mind as well as the discriminatory quality of his nose.

The 2 components of the ground scent picture are the footstep on the ground and the rafts which have come to rest on the earth.

A footstep on the soil will not create a disturbance of the soil.

The fact that vegetation is crushed by a footstep will have not anything to do with the ground scent picture.

Lush vegetation will provide more soil bacteria and therefore more scent than will dry sand and gravel.

Crushed vegetation provides nutrients for the bacteria that live in the soil resulting in the release of various odor producing chemicals.

The amount of vapor or odor containing gases produced in the area of one footstep has nothing to do with the size of the person’s foot or how much the person weighs.

The vapors coming off the area of the footsteps are different and more intense than the surrounding area.

The odors coming from the crushed vegetation and soil disturbance are the same as a person’s body scent as that person walks on that particular area.

The odors coming from the crushed vegetation and soil disturbance are the same as a person’s body scent as that person walks on that particular area.

If wind conditions are right, the vapors coming off each footstep tend to link together to form a tunnel of vapor over the pattern of a person’s footsteps.

When rafts come to fall on the ground they become part of the ground scent picture.

Rafts that fall on very hot sand will give a greater and longer production of odorous vapor than rafts that fall on to cooler,
ccccsshaded areas.

Because soil conditions vary from acre to acre, it is impossible to know how long vapors will be given off.

Moisture or humidity has little effect on the action of bacteria with regard to the ground picture.

Sunlight seriously affects bacteria with some rays actually having the power to destroy bacteria.

Wind conditions will have an effect on how rafts fall to the ground along any particular route.

When a person’s foot hits the ground, the following three factors develop: (1) vegetative fluids are released, (2) vapor enshrouded rafts fall to the ground, and (3) the plant cells that are crushed by the foot start to decompose on or in the soil.

The fact that certain plants have different and pronounced odors means that they may produce background odors that can mask the odor which is being sought.

Cedar, mint, skunk cabbage and onions are plants that produce strong background odors that might mask other odors.

Odors from vegetative fluids like mint or elderberry tend to last longer than the odors from dead cells of plants.

Vegetative scent tends to be more intense and last longer than human scent.

Regarding ground scent, two of the reasons the vapor from rafts last for a shorter period of time compared to dead plant cell vapors is that the raft vapor process was already underway when the rafts left the body and there are relatively fewer dead skin cells compared to dead plant cells.

Variations in temperature have the biggest effect on odors resulting from bacterial activity.

Tests designed to show how temperature affects scenting conditions indicated that all things being equal, scenting conditions are better around noontime.

Studies show that airborne rafts are subject to less extreme temperatures than rafts that have landed on the ground.

Moisture must be present for bacterial activity to continue.

The intensity of scent increases during early evening because dew forms on the grass and provides hydration so that bacteria have a food supply.

Rafts there were deposited around noon would best be perceived around evening.

Rafts that were deposited in the evening would be best perceived at noon the following day.

If a footstep on the ground is shaded by a large leaf, the intensity of the scent of the footstep can be increased or decreased by whether it is shaded or exposed to sunlight as the sun changes position throughout the day.

A footstep in the shade will have a less intense scent than one exposed to sunlight.

The scent of the entire ground picture is composed of 2 main vapors: (1) the vapor of bacteria working on human dead skin cells (rafts) and (2) vapors produced by soil bacteria working on dead plant cells (plants are killed when they are stepped on).

The odor given off by each human is the same for each person.

The odor given off by each killed plant differs depending on the plant.

Vegetative odors persist longer than human odors.

When a human walks over the ground, the majority of rafts falling from his body will be dispersed over a wide area, depending on the wind.

In general, vapor from rafts falling from the body tends to last a long time.

Very few rafts falling from the human body tend to fall near the person’s footsteps.

Dead plant vapors do not help a dog discriminate the scent of one human from another.

It may appear that a dog is following the footsteps of a particular person when in reality he is following dead plant vapor.

A dog would have difficulty telling the difference between two sets of footprints that crossed each other if they were made at the same time and by a person of the same weight and shoe size.

It is just as easy for a dog to follow a scent over a hard surface like a road or concrete as it is to follow a scent over vegetation.

Rafts (dead skin cells) that fall into cracks or crevices on a hot, dry surface may rehydrate at dark and provide a food supply for the bacteria.

Porous and uneven surfaces like sandstone, rock slides and course asphalt, will support bacterial growth longer than other hard surfaces.

Within the strict definition of the term, a tracking dog should indicate almost each one of the subject’s footsteps.

A tracking dog and trailing dog are the same thing.

It’s OK for a tracking dog to move more than 2 feet from the subject’s footsteps.

A trailing dog can take shortcuts as he follows a subject’s footsteps.

A basic orientation of the tracking dog is leaves of vegetation.

Tracking dogs are characterized by keeping their nose to ground.

Trailing dogs may sniff at vegetation 2 or 3 feet off the ground.

Based on Syrotuck’s definition, a trailing dog and air scent dog are the same thing.

An air scent dog may completely ignore the ground scent.

The tracking dog’s training is oriented to following footsteps.

“Tracking” dogs may have to be taught how to discriminate by training on predominantly hard dry ground with sparse vegetation.

“Trailing” dogs need to be allowed to work some distance from the exact route.

Syrotuck calls air scenting dogs, point source dogs.

There is only one kind of point source oriented dogs.

Point source oriented dogs are characterized by a nose to the ground posture.

The exclusively nose to the ground type of dog has the highest discriminatory potential.

In point source training, it is important to practice with a variety of locations.

A benefit to point source search training is that it has varied applications.

In searching for the source of a scent, the amount of time that has passed is irrelevant.

In searching for the source of a scent, the amount of time that has passed is irrelevant.

In searching for humans, we must decide if we need a dog to simply detect a scent to discriminate among various human scents.

In searching for a victim lost in a wilderness area, dogs that are detection trained can be effective.

A tracking dog uses a discrimination method.

The following are necessary for both a tracking and a detection dog to perform: getting to the scene early enough; having favorable atmospheric conditions; and having an available article of clothing.

Usually police work involving crime scenes require a dog who can discriminate.

Dogs need to be trained either to do discrimination work or detection work based on the problem that needs to be solved.

No dogs have ever been trained as “prospecting dogs” who can detect various kinds of mineral deposits.

A pitfall of the tracking dog is that because he learns to associate footsteps as being a cue for a victim, he may fail to develop and use other talents like sight, sound and sniffing air currents.

Sometimes a dog can become so “footstep happy” he may pick up and work any set of ground disturbance patterns in order to please his/her master.

Sometimes a dog can become so “footstep happy” he may pick up and work any set of ground disturbance patterns in order to please his/her master.

It is unusual for older or over-trained dogs to consistently overshoot a track that has turned.

It is unusual for older or over-trained dogs to consistently overshoot a track that has turned.

If a dog appears always eager and happy to go tracking, it is always an indication that he really likes to do the job.

Kennel dogs are more prone to looking eager to work when in reality they are more excited just to be going some place.

Dogs that are punished for making a mistake are more likely to fake following a scent.

Dogs that are trained to work in front of a handler will never get miscues from the handler with regard to which direction to turn.

AKC tracking tests require a harness and leash.

A harness and leash can be used as safety equipment when dogs are working cliff areas or a source of identification for dogs in Europe.

Syrotuck feels that from a practical application, the leash and harness are always necessary.

Voice commands should never be used with a tracking dog.

A leash and harness can inhibit a tracking dog’s freedom of movement and ability to investigate.

A leash and harness can inhibit a tracking dog’s freedom of movement and ability to investigate.

The leash is an advantage in heavy underbrush.

Less frequent rest stops are necessary when using  a leash and harness.

Bloodhounds typically need a leash and harness.

A dog that is searching for a lost individual in the wilderness will typically use a random search pattern.

In a random search pattern the dog is out ahead of the handler and is casting back and forth.

Avalanche dogs often use a signalled search pattern.

A signaled search pattern and a random search pattern are the same thing.

Police departments who have trained marijuana dogs most often use the signalled search pattern.

Some feel the signalled search pattern may interrupt the dog’s concentration because he is always waiting for a command from his/her handler.

A routine search pattern is one of the preferred patterns for locating an avalanche pattern.

It is always beneficial to attach bells and lights to unleashed scenting dogs in the dark.

Bells and lights are especially important for police dogs working at night.

Snow increases bacterial activity and improves scenting conditions.

The best snow condition for scent is very loose and dry snow.

The worst snow condition for scent is wet snow.

With regard to different layers of snowfall, the top layer will be the warmest.

It is almost impossible for a dog to “track” a person who has walked over a snow surface.

Scent intensity will be highest on the snow surface.

Dogs can easily follow footprints in the snow as long as there are no other footprints; if other footprints are present he/she must discriminate.

It is possible to follow a track that was laid on bare ground and then covered by melted snow.

Rafts that have fallen on bare ground and are subsequently covered by melting snow, can float to the surface of the snow.

For victims that are covered by a snowfall, under normal circumstances, an average dog can detect their vapors through a layer of snow 12 feet deep.

If a victim is covered by several different layers of snow it can diminish the amount of vapors that reach the surface.

It’s easier for a dog to detect a person who is buried under heavy, very wet snow.

It’s easier for a dog to detect a person who is buried under heavy, very wet snow.

In an Austrian experiment, dogs were not able to follow a tract made by a wheel built with foot pads on the rim.

As long as a track was started with human footsteps, a dog did not differentiate between human and wooden footsteps.

Vegetative vapors don’t give dogs any discriminative information.

Dogs that are trained on rafts are better able to learn how to discriminate.

Wetting a dog’s nose to keep it moist will not improve its scenting ability.

Tracking, trailing and air scenting are better in a warm and humid environment as opposed to a hot and dry one.

It is easier to track and trail on hot sand.

A light rain can be beneficial because it rehydrates the bacterial activity.

A prolonged rain is the best scenario for the scent picture.

It is likely that scent particles have a certain initial velocity.

Scent is easily perceptible upwind.

It is very easy for a dog to track on a hard surface like a road.

Dogs can detect humans in swamp areas as long as the dog’s working ability is not interfered with.

It is impossible for a dog to find a person who has crossed a stream.

The scent of someone who has crossed a narrow stream is usually found along the banks of the stream and downstream.

Following a scent at night can be easier than during the day.

A 30 minute track is harder to follow than a 10 minute track.

Porous objects like shoes, wallets and gloves will absorb a scent better than non-porous objects like metal watch bands or plastic belts.

When a person handles an object there is a direct transfer of skin secretions, cells and bacteria.

Even if an article is bleached, scent cannot be removed from it.

Even if an article is bleached, scent cannot be removed from it.

Leaving a scent article in the sun will not destroy the scent.

It is technically impossible for a human to avoid detection by a dog.

A person's breath will not leave a scent.

It is possible to mask marijuana so it cannot be detected by a dog.