Our work at BOSInd is based on sound scientific principles.

Human reaction to odours

“The smell nerve receptors are linked directly to the brain, man. There’s like, nothing… nothing between them and the brain, they’re totally unlike all our other senses… it’s cosmic.”

– Dr Timothy Leary

Deep within each nasal cavity of all humans is a patch of cells called the olfactory epithelium. Each 2.5 cm2 patch contains about 50 million sensory receptor cells. These receptor cells send their axons into the olfactory bulb, a projection of the brain that lies over the nasal cavity in most primates. From the olfactory bulb, the signal is transmitted to the limbic system in the brain where memory is used to recognize the odour.

The limbic system is not only a memory storage area but it also regulates mood and emotion.

Since odours, emotions and memories meet here, smell elicits distinct memories and emotions. The perception of a certain odour that is associated with a past memory allows for recognition of the odour in the olfactory system and a corresponding past memory.

A question arises as to how the limbic system is able to remember past smells, while olfactory neurons are continually replaced every sixty days. The reason is believed to be this: when the olfactory neurons die, a new set of neurons generates beneath them, inheriting the same neural causeways. These axons of neurons that express the same receptor always lead to the same destination. This is how memories survive in the limbic system.


Isolating smell

The widest range of odours consists of organic compounds, although some inorganic substances – such as hydrogen sulphide and ammonia – are also odourants.

Since the 1870s concentrations of odourants have been defined by the Olfaktometrie, which helps to analyze the human sense of smell using the following parameters: odour substance concentration, intensity of odour, and hedonic assessment.

It has been proposed that there are seven primary odors:

1.) Musky – perfumes and aftershave

2.) Putrid – rotten eggs

3.) Pungent – vinegar

4.) Camphoraceous – mothballs

5.) Ethereal – dry cleaning fluid

6.) Floral – roses

7.) Pepperminty – mint gum

It is not clear if our ancient ancestors had any experience of group 5

A short–lived research project to investigate this was undertaken in Mexico during the early 1970s using organic gases, peyote and alkyl nitrites; however, the project was abandoned due to various medical and mental issues amongst the team.


Measuring smell

Since 1887 the concentrations of odourants had been established using a panel of human noses as sensors and the concentration of the odour expressed in terms of European Odour Units (ouE/m≥).

The main panel calibration gas used is Butan-1-ol, which at a certain dilution point (the point at which the odour is only just detectable to 50% of the test panel) gives a concentration measurement of 1 OUE/m3.

Naturally this method was hardly scientific, as it depended on organisms and opinions. What was needed was a machine measurement – it was Dr Sydney Rann who provided the much-needed breakthrough.


Butane molecule: Messy

Dr Rann’s seismic idea – reputedly arrived at after a heavy meal of re-fried beans – was to use methane as a calibration gas.


Methane Molecule: Cute

Methane molecules, with 4 hydrogen and only one carbon atom, are bound by a constant magnetic field and therefore can be measured by the use of mass spectrometry – this is unlike the unwieldy, and magnetically variable, butane molecule.

The paradox which Dr Rann’s genius solved was that although organic compounds bound to methane molecules would, to a panel of human noses, smell like a field of rotting cabbage, a Geographic Assimilation and Separation Processor (G.A.S.P.) could precisely identify and measure such organic compounds.


Odour as mood stimulant

It is in this field that some of BOSInd’s most interesting work has taken place, and where the rock face of smell meets the mountain goat of physiology.

Dr Rann maintained an interest in the physiological effects of smell from his student days. In the 1970’s BOSInd’s Chelsea facilities became famous for both the cutting-edge experimentation of our research laboratory staff and the popularity of our social events.

After an unfortunate incident involving two young research assistants, a male sea otter and a vat of pheromone impregnated massage oil, Dr Rann decided to move the facility to the more studious surroundings of Wastrel Peak on the Yorkshire moors. Here, undisturbed by the distractions of society and restrictive Health and Safety inspections, Dr Rann laid the foundations of the BOSInd Detection Of Odour in Mood System. The D.O.O.M. system replaced previous studies which merely studied the physiological effects of smell with an empirically-based search for the odours and chemicals present when a target behaviour pattern occurs.

In his seminal paper ‘Presbyterian Priests:Induced Polka, Manicures and Cross-dressing from Impregnated Cheese and Crackers’ (Nature, Vol. IIV, 1986), Dr Rann gained international respect and recognition as a force to be reckoned with.

The last 20 years have seen BOSInd consolidate its position as the world leader in mood stimulating odour research.