Louis Pasteur – A Pioneer: Contributions of Pasteur to the Development of Microbiology

Louis Pasteur, one of the greatest scientists the world has seen, was born on December 27, 1822, in Dole, France. His father was a poor tanner but he wanted Louis to get a good education. Pasteur attended school in a nearby town called Arbois. His headmaster saw potential in him and encouraged him to go to Paris to further his education.

Early Life of Louis Pasteur

Pasteur’s first sojourn to Paris did not go too well. He got homesick and came back to study in a town called Besancon, where he received degrees in Letters and Mathematical Sciences. He got admitted to an elite college in Paris called Ecole Normale Superieure. He obtained his doctorate degree in 1847 and a year later he became professor of Chemistry at the University of Strasbourg. He courted and married Marie Laurent, the daughter of the University Hostel’s Rector, in 1849.

Birth of Stereochemistry

Pasteur’s first landmark contribution was to the field of chemistry where he showed the presence of chiral molecules of sodium ammonium tartarate. Chiral compounds have the same molecular formula but they are mirror images of each other. This discovery triggered the search for chiral molecules of many other compounds giving rise to a new branch of chemistry called Stereochemistry. In 1856, he was made the administrator and director of scientific studies at Ecole. By 1857, Pasteur had become a world famous scientist.


During his time at the University of Lille, Pasteur was approached by the wine manufacturers of the region. They were concerned about many recent batches of their wine turning sour and this problem was seriously affecting the reputation (and profits) of the famous French Wine Industry. Careful analysis by Pasteur showed that a bacterium had “contaminated” the wine fermentation batches and was producing an acid which was resulting in souring of the wine.

He found out that gentle heating of the wine to around sixty degrees centigrade for about thirty minutes was enough to destroy the bacterium and prevent souring. This came as a great relief for the French Wine Industry and also helped Pasteur’s reputation go far and wide. This technique of Pasteur’s was applied to other beverages as well and particularly to milk where it came to be known as pasteurization.

Discovery of Germ-Disease Relationship

Pasteur also rescued the French Silk Industry which was plagued by a disease called pebrine which affected the caterpillars which died before making their cocoons. Pasteur found out that the disease was caused by a bacterium. He thus found out the connection between bacteria and diseases. He worked with the silk industry to devise methods to keep their hatcheries bacteria-free and thus, disease-free.

Discovery of Attenuation

One of the most important discoveries of Pasteur is, without doubt, attenuation. He was working on a disease which plagued chickens and was affecting the poultry farmers of France. This disease called “chicken cholera” was caused by a bacterium. Pasteur isolated the bacteria from diseased chickens, cultured them outside and when he inoculated this fresh culture into healthy chickens, they developed the disease and died. Legend has it that he left a bottle of culture in his laboratory and went for a couple of weeks’ vacation. When he returned, he inoculated the “old” culture into healthy chickens. The chickens became sick but recovered, much to the chagrin of Pasteur who had expected them to die.

Pasteur then inoculated fresh “virulent” bacterial culture into the same chicken, which surprisingly, failed to die. Pasteur deduced that the bacterial culture had lost its “virulence” or disease-causing ability and had been “attenuated.” This forms the basis of vaccination. Pasteur applied this technique to help protect sheep from anthrax, another fatal bacterial disease. But Pasteur is best remembered for his work on the rabies vaccine, the first human vaccine.

The Rabies Vaccine

Pasteur inoculated the fluid taken from a rabid dog that had just died, into a rabbit. The rabbit developed rabies and died. Pasteur removed the spinal cord of the rabbit, dried it and powdered it. He injected this into a healthy rabbit, which was later inoculated with the virulent inoculums. The rabbit failed to develop rabies. The first person on whom the rabies vaccine was tested was a young boy named Joseph Meister. The boy repaid the benevolence of Pasteur by returning to Paris and working for him. When Meister was key keeper of the Pasteur Institute in Paris, the Nazis raided it and forced Meister to hand over the keys of Pasteur’s crypt. Instead of handing over the keys and betraying his benefactor, Meister shot himself.

Pasteur dedicated his entire life to the goodwill of humankind. He faced personal tragedies during his life with three of his five children dying at a young age. It is a general belief that had the Nobel Prize been instituted earlier, Pasteur would have won it a number of times for his various important contributions. Pasteur died on September 18, 1895 from complications arising from a stroke he had suffered a few years previously.

Bruce Lipton’s The Biology of Belief: A Look at Unleashing the Power of Consciousness, Positive Thought

In the Biology of Belief, Bruce Lipton lays a scientific foundation that positive thoughts are a biological mandate for a happy, healthy life.

Bruce Lipton, Ph.D., is a cell biologist and his book The Biology of Belief: Unleashing the Power of Consciousness, Matter & Miracles is about how his work with cells led him to believe that genes and DNA do not control a person’s biology.

Rather, Lipton claims that signals from outside the cell, including the energy from positive and negative thoughts, control biology.

Lipton’s Theory on Cell Receptors

All cells have receptors that respond to their environment. For example, receptors detect estrogen, insulin, histamines, etc., which is how these substances affect the body’s cells. But not only do a cell’s receptors respond to physical substances, they also respond to vibrational energy fields such as light, sound, and radio frequencies.

Lipton’s research with cells led him to the conclusion that it is not the DNA in the cell’s nucleus that “programs” the cell, as traditionally believed, but the signals that come in through the cell’s receptors. That is, the physical and energetic environment controls the life of a cell.

Biology and Quantum Physics

According to quantum physics, physical atoms are made up of spinning, vibrating vortices of energy. Each atom has its own specific energy signature, and collections of atoms (molecules) have their own identifying energy patterns. All physical matter is made up of molecules, including human beings, and each piece of matter (or person) radiates its own unique energy signature.

Lipton points out that because Western biologists have ignored the energy component while focusing on the physical things that affect cells. Lipton claims that they have arrogantly dismissed 3,000 years of effective Eastern medicine as unscientific, even though it’s actually based on a deeper understanding of the universe. Lipton goes on to say that, “vibrational frequencies can alter the physical and chemical properties of an atom as surely as physical signals like histamine and estrogen.”

Thoughts and Perceptions

Lipton claims that cells respond to vibrational frequencies. Thoughts and perceptions are vibrational frequencies; therefore, cells respond to thoughts and perceptions. The problem is that not all a person’s thoughts and learned perceptions are accurate.

Biologically speaking, human brains have the ability to rapidly download “an unimaginable number of beliefs and behaviors into our memory.” The subconscious minds of young children become programmed with the fundamental behaviors, beliefs, and attitudes that are observed in their parents. These programs control a person’s biology for the rest of their lives, unless they consciously figure out a way to reprogram the mind.

A stimulus automatically engages the behavioral response that was learned when the signal was first experienced. Although the conscious mind can observe what is happening and step in and change the behavior, a person must be fully conscious. This can be difficult, which is why willpower so often fails.

Methods for Changing Perceptions

Although the Biology of Belief explains the science of why thoughts and perceptions are important, and even notes that a person can choose what to see, and choosing to look at negative rather than the positive aspects of life makes a person susceptible to disease,

Lipton doesn’t actually get into how to change thoughts and perceptions. However, many methods are available today to change beliefs, including Emotional Freedom Techniques (EFT), the Sedona Method or Abundance Course (also known as Lester Levenson’s Release Technique), Ho’oponopono, the Work of Byron Katie, and PSYCH-K.

Lipton concludes that because controlling perceptions equal beliefs, beliefs control biology. And that leads to the conclusions that learning to harness you mind to promote growth is the secret of life, and positive thoughts are a biological mandate for a happy, healthy life.

The Science of Autumn or Fall Leaves: Why Do Leaves Change Colour and Fall From the Trees?

Autumn’s beauty is clear for all to see, the myriad shades of red, yellow and brown lifting the heart on a cold but bright October morning. But the curious mind wonders “Why?” Why do the trees go through this process every year, only to grow fresh leaves every spring? And why such a variety of colours and shades – of which any artist would be proud?

Using Chlorophyll

The green leaves of summer contain chlorophyll, which drives photosynthesis – the molecular factory transforming carbon dioxide and light into glucose – which gives energy to the plant and cellulose for growth. When summer ends and autumn arrives, it is the short days which trigger the changes in deciduous trees. The chlorophyll is taken back from the leaves to be recycled, but the leaves become not just superfluous, but a liability.

Abscission Zones

In order to exert a force of suction, to draw water from the ground during the summer, leaves sweat through their high surface area. In winter these same leaves could cause the trees to dry out and die, so they must be removed. The scientific process of leaf-removal is known as abscission. When the shorter days of Autumn arrive, a number of chemical changes occur and the abscission zone at the base of the year begins to swell, cutting off the flow of nutrients from the tree to the leaf and vice-versa. The zone then begins to tear, the leaf falls off or is blown away, and a protective layer seals the wound, preventing water evaporation and entry of bugs.

Anthocyanins and Aphids

But why do the leaves go so many different colours? The removal of the chlorophyll reveals other colours in the leaf – yellow, orange and brown – but some leaves turn red or purple for another important reason. The shorter days which trigger the process of abscission, also initiate another process in the leaves of certain trees to produce a group of chemicals called anthocyanins, which are deep red or purple in colour. This is not, however, just vanity on behalf of the tree.

In fact, the red colours are used to conceal the shades of yellow which attract aphids. So, trees which are more susceptible to aphids, or are native to areas where aphids are more of a problem, are able to confuse their enemies and survive to grace another spring.

The Structure and Growth of Flowering Plants: A Comparison Between Monocots and Dicots

An overview of the structure and function of an angiosperms’ root system, stem and leaves, and flowering plant’s adaptations to their environment.

Angiosperms are the most diverse and widespread group of plants. There are over 280,000 known species of flowering plants.

Plant Adaptations to the Environment

Like other organisms, plants have evolved over time, often reflecting the environment in which they live. For example, the cactus that has reduced its leaf size and uses its stem for photosynthesis as a way of reducing water loss. Or plants that live in water that have adapted feathery leaves to increase surface area for photosynthesis.

For most plants however, conditions are not that extreme, and could vary on a daily, weekly or seasonal basis. Because of this, plants have developed physiological adaptations.

Plants produce a hormone that closes stomata when there is not much rainfall or water in soil. Stomata are pores in the plant leaves through which water is lost, or released. In wetter conditions, plants will open their stomata to excrete extra water.

The Difference Between Monocots and Dicots


  • One cotyledon (embryo)
  • Veins in leaves usually parallel
  • Stems have vascular bundles, complexly arranged
  • Fibrous root system
  • Floral parts usually in multiples of threes

Examples of monocots include grasses (wheat, rice, corn), cattails, lilies, palms trees, orchids, bamboos and yuccas.


  • Two cotyledons
  • Leaf veins are usually netlike
  • Stems have vascular bundles arranged in a ring
  • Taproot usually present
  • Floral parts usually in multiples of four or five

Examples of dicots include many trees, and most ornamental and crop plants such as roses, sunflowers or beans.

Plant Structure

The three basic organs of a plant are:

  • Roots
  • Stems
  • Leaves

Plants are multi-cellular organisms. They have organs composed of different tissues, and tissues composed of different cells.

Plant Roots

A plant’s roots are what anchors it to the soil and how the plant takes up nutrients. Monocots have fibrous root systems that expand a mat of thin roots below the surface of the soil to increase the plants exposure to water and minerals.

Dicots have a taproot, which is one large root, which produces smaller lateral roots. These taproots often store food for the plant to consume during flowering and fruit production.

One both monocot and dicot root systems are tiny root hairs, which reside near the root tip. The purpose of these root hairs is to increase the surface area of the root for optimal absorption of water and minerals.

Plant Stems

Plant stems are a system of nodes, internodes, axillary buds and terminal buds.

  • Nodes: the point where leaves attach to stem
  • Internodes: stem segments between nodes
  • Axillary buds: structures that can form vegetative branches, but are usually dormant
  • Terminal buds: where growth of young shoots occurs. Terminal buds have developing leaves and a complete series of nodes and internodes. Terminal buds suppress the growth of axillary buds. This is referred to as apical dominance.

Apical dominance is an evolutionary adaptation that makes the plant grow taller and this exposes the plant to more sunlight. In cases where the top of the plant is damaged (ie: eaten by an animal), or light intensity is strongest at the sides of the plant then the top, axillary buds break dormancy and start to grow, complete with their own terminal buds, axillary buds and leaves.

Plant Leaves

Most photosynthesis occurs in the leaves although green stems can also perform photosynthesis. Leaves generally consist of:

  • A flattened blade
  • A stalk
  • The petiole: which joins the leaf to the node of the stem

Leaves can vary in structure, however. Grasses for example (and many other monocots) lack petioles. Instead the leaf base forms a sheath around the stem. Plant taxonomists use plant leaves to determine plant identity and classification.

Differences in plant leaves aside from shape, spatial arrangement and vein pattern, are:

  • Simple leaf: leaf that has a single, undivided blade
  • Compound leaf: which are divided into several leaflets
  • Double compound leaf: leaf that is further divided into several leaflets

Most large leaves are compound leaves or doubly compound, which allows for strength against strong wind (less tearing) and protection against pathogen spread (ie: able to confine some pathogens to a single leaf rather then whole leaf).