1- The mysteries of the Purr.

Most felines, from the domestic cat to the lion and the panther can emit a deep and caracteristic vibration, the purr. This purring starts when the cat is very young and continues well into old age. We still don't know the exact mechanism.

For a long time it was thought to be a vibration from the folds of the larynx but felines having undergone a laryngectomy, (Hardie and Co-1981) continue to purr.. The diaphragm has been invoked (Stogdale1985) but current opinion suggests that purring is the result of blood flow in the vena cava: this vein narrows to pass into the liver and the diaphragm. In certain neurovegetative states the blood will form ripples in this bottleneck which then provoke vibrations in the body all the way up to the cranial cavities of the sinus by way of the windpipe..

In fact everything vibrates and the cat takes on a caracteristic relaxed (laid back) attitude. This relaxed state was for a long time associated with contentment, however cats that are in pain or distress also purr. The phenomenon of resonance: this is a physical phenomenon that touches all media in all frequencies. When one element of a medium starts to vibrate, the whole medium vibrates to the same frequence reinforcing the original sound. The violin is a good analogy: when the bow is drawn across a chord, the whole violin vibrates to produce a harmonious sound. When a cat purrs the same effect occurs in the body and everything vibrates.

2-The enigma of frequence 25/50 hertz.

If we analyse the sound spectrum of a cat's purr we see mainly deep sounds ranging in frequence between 25/50 hertz. These are "bass" sounds, well known to music composers for they provoke emotions and therefore have a direct influence on an organism. Can such an action be measured ?

The organisation for animal protection Animal Voice, that studies many forms of animal communication has carried out research on the subject.
Orthopedic doctors have used these frequencies to consolidate fractures and successfully treat degenerative osteoarthritis. The published results show an acceleration of the healing process and the creation of new tissue. In short these bass frequencies have an anabolic action.
At the same time, the researchers at Animal Voice have found statistics in veterinary universities showing that for the same lesion and with the same surgical treatment cats have five times fewer after effects and recuperate three times more quickly....
Hence the hypothesis of an anabolic recovery: purring has a real therapeutic effect !

3-Happiness or distress..... Recovery time.

Whilst treating cats in distress, veterinary surgeons have noticed that suffering animals still find the force to purr. Here we are far from the image of the contented cat purring in the arms of it's master....
All the same, in both cases purring is associated with the recovery process.
With a contented cat, sleep and happiness are well known to be anabolic states. It is whilst we sleep that we grow, build tissues and structure the memories of the days events.
With a cat in distress we can interpret purring as a desperate reaction of the organism to resist the disease. This phase of recovery and consolidation is controlled by the brain through the autonomic nervous system.

4-The Autonomic nervous system.

Permanently and to the best of our knowledge, the nervous system surveys the body and regulates our organs. The heartbeat, the muscles of the iris, retention of the bladder, all the major involuntary activities of the body are controlled by bundles of nerve fibres: the autonomic nervous system.
These fibres function independantly of our control and effect all the organs of the body. They control the passage of food through the gut, the inhalation and exhalation of air in the lungs, blood circulation etc. They also activate the glands and therefore control the production of hormones. ..
This autonomic nervous system, whose main function is to maintain the body in a stable state, is composed of two opposing and complementary parts, the sympathetic system and the parasympathetic system.

The sympathetic system , whose nerve fibres are activated by the production of noradrenalin, prepares the body for an emergency by mobilising all defenses, increasing heartbeat, raising blood sugar level, constricting arteries. Fight or flight.....
It is the sympathetic nervous system that keeps the body alert and controls our degree of agressivity by the production of dopamine.
When the sympathetic system is called into action the body works very hard and rapidly consumes it's reserves, all the cell membranes depolarise.

Inversely the parasympathetic nervous system stimulates the production of serotonin (the sleeping hormone).
Serotonin is produced during the day and stored in certain parts of the brain ( pre-optic cavities). It gradually overrides an alert state and sleep can ensue. Whilst an organism is sleeping it can build up it's forces. It is often upon waking in the morning that one feels cured of a viral or bacteriological infection. .
The hypothesis of endorphines: endorphines are endogenous morphines secreted by nerve tissue, either to combat pain, or paradoxically to accompany a feeling of happiness and fulfilment. It is in these two cases that a cat begins to purr. Researchers think that purring produces endorphines that allow the animal to ease it's own pain and also to achieve visible serenity. ....

5-Memories and emotions.

All the stimuli that activate the brain, whether they are external (sound, light) or internal (thoughts, organic sensations) pass through two important centres in the brain. The hippocampus, that recognises and categorises events and objects and the amygdala that correlates emotional sensations as well as colours.
For example. You see, passing rapidly in the street, a blue moped. The exact model that you had fifteen years ago. Immediately the vision crystalises in the hippocampus (factual memory recall) and enlarges in the amygdala where a thousand details about your moped, colour, smell of the saddle, sensation of speed, awake your emotions. It is a powerful memory.
The sense of smell constitutes the strongest input, before sight and sound.

So it is that certain estate agents toast bread and brew coffee in an appartement they wish to sell. Potential buyers are seduced by the aromas that invoke a sense of well being, associated with ideas of the family, happiness, welcome etc....

6-The Purr, like "Proust's Madeleine" ?

Have you known marvellous moments shared with a small round ball of fur that purrs loudly in complete trust as if to proclaim it's happiness? The sound of purring stimulates the hippocampus and amygdale and has the effect of "Proust's Madeleine".
Proust is a famous french writer who wrote in one of his books, how simply to eat a madeleine (small sponge finger) dipped in a cup of tea brought back many happy childhood memories. Listening to a cat purring takes us back to a time when worries were inexistant, no stress or anxiety.
Is there action from neurotransmitters or hormones ?
About thirty factors have been described that participate in the induction of sleep. Their interactions are relatively unknown for the time being, especially as they all have other biological activities.
When listening to a cat purring the neurones that produce serotonin can be activated along the hippocampus and the amygdale. In fact everything happens as if the emotions awakened by the sound of the cat purring stimulate the production or at least the release of serotonin which enduces a state of serenity and drowsiness.
To resume, when a cat purrs, calming substances are produced, either serotonin or endorphines. The result is before our eyes, we would all like to share it.

7- Purring , a voyage of discovery

The magazine Effervesciences has edited an audio CD that contains several tracks of purring, with and without a musical accompaniment.
More than 250 readers or websurfers have ordered this CD to test for themselves the effects of a recorded purring. for many it is not the same as the real thing, which is normal, however about thirty adepts of the purr have taken the time to give their impressions. Here are a few comments:

-" Really helped to send me to sleep·".
-" As well as the familiar sound of the purr, one can discern the life force of the cat, a remarkably sensitive being·".
-" Profound relaxation with the perception of a violet light·".
-" An immediate and noticable decrease in stress·".
-" I noticed the ciculation of energy with a sensation of pins and needles in the palms of the hands and feet. After quarter of an hour, a deep and even respiration set in that brought a feeling of calm·".

You should listen to this CD in a calm place with a low volume, if possible with earphones. Find a comfortable position and do not "nibble".
You should not listen to this CD whilst driving.

8-Join the adepts of the purr.

The europeans have been able to get this cd since 2003, and there are now thousands of them who cannot live without this vibrations, without this magical and mysterious sound enclosing their spirit with serenity leading to a peacefull sleep.

This cd, for practical reasons such as long postal delays, or for economical reasons ( cost of transport, lost of parcels), cannot be sold out of Europ. Does this means that the americans, or the africans, weither the asians could not benefit from the healing purrs ?

The solution is called INTERNET ... We have now put on our website a group of MP3 files ( 6 exactly), containing 30 minutes ( really enough to feel softly sleepy...) of the most efficient purring, we proudly present Rouky's purring, but also a mix of the purr sound with calm and tranquil melodies, and all this for only ten euros . You can pay on the internet ( secured payment for credit cards) and then receive the code for the site where you will download these files one by one to your computer, and then to record them to a cd you will be able to listen to anytime you like, or give to friends around you that have problems to go asleep ....TO DOWNLOAD ROUKY'S PURR , IT'S HERE

His purr will ease your mind and procure an attitude of serenity, leading to a calm and peaceful sleep.

Please let us know your impressions by email and we will be happy to add them to our list

Jean-Yves Gauchet