“A bond is the glue that makes parts whole”


No man is an island, entire of itself;

every man is a piece of the continent,  a part of the main. “

John Donne’s “Meditation XVII: – Devotions upon Emergent Occasions”

In the introduction to parts we touched on the profound importance of organization, connection and integration.  The only way that “units to unity” can materialize is through strong and meaningful connections.  This concept applies not only to the parts of the body but also to pieces of information.  Information in isolation is meaningless.  It is through connections and integration that information becomes knowledge.

The manner in which the parts are connected and related is the key to the genius of biology.

At The Organ Level

Some of the Bonding Structures

Blood Vessels Lymphatic and Nerves
Structural Bonds in the Body
Ashley Davidoff

……that enable the organs to bond and collaborate  to form the body

Organs of the Body
The organs of the body, bond in structure and function to create a single entity – the body
The brain is the central controlling and integrating organ of the body and it is linked to the organs via nerves. Blood vessels, ducts and hormones also serve to connect the organs
Copyright Ashley Davidoff MD

At the Cellular Level

Bonding of Organelles to Form the Cell

Organelles of the Cell
The organelles of the cell bond in structure and function to create a single entity – the cell
The nucleus is the central focus of the cell and it is bonded to the organelles including the smooth and rough endoplasmic reticula, Golgi apparatus, mitochondrion, lysosome, and messenger RNA.
Ashley Davidoff MD

37.2 Trillion Cells in One Body Can Work Co-operatively -Why Cant We?

Bonding in the Body
The Cells know how to do it- Why don’t we?
Ashley Davidoff
Muscles Connected to Each Other Via the Bones, Tendons and Ligaments
Ashley Davidoff
Muscles Connected to Each Other Via the Bones, Tendons and Ligaments
Ashley Davidoff

The connection of the knee bone to the thigh bone, the thigh bone to the pelvis and the pelvis to the sigmoid shaped spine, allowed homo sapiens to evolve into an upright animal, and liberated the upper limbs.  The upright posture, together with an advanced brain, afforded man the opportunity to develop tools, manipulate his environment, and think.  Thus humans were afforded a huge advantage in the biological environment.

At the molecular end of the spectrum, the exact pattern in which nucleic acids adenine, guanine, thymine and cytosine are sequenced or connected on DNA strands  an individual’s genetic fate.

At the cellular level the 250 billion cells of the liver need to be connected related and integrated in a way that enables them to act as a single unit, as the metabolic warehouse of the body.  The world population is currently (April 2009) estimated at a mere 6.8 billion.  The ability of nature to organize 250 billion cells into a single harmonious group is a lesson to be learned and an amazing story to be told.

For the liver to function, it is imperative that the transport systems be in intimate contact with cells in order that food, oxygen, and water are transposed and that waste products are removed.  Two hundred and fifty billion cells of the liver need to be connected, related, and integrated in a way that they are able to act as a single functional unit.  The elegant organization of liver cells and cords in the liver lobule was described in the section on Parts above.  The key element for the cell is how it can be connected to structures it depends on. The cells of each organ deal with this problem in a different way.  Therefore, when studying the histology of the gastrointestinal tract, the pancreas, or the lung, note will be made of differing organizational patterns that optimize function.  These patterns are relevant not only to marvel at the genius of nature, but also to understand that when disease distorts the structure, function will suffer.

Skeletal System exemplifies the concept of parts and bonds magnificently

Muscular System  also from 7active studio

At societal level, human connections are vital for the health of the individual and of society. An elderly patient whose children and grandchildren have moved out of state, and who lives alone, becomes disconnected from the pulse of life and society.  For the patient, incorporation into peer groups and into the mainstream is essential for well being and health.

The knowledge of how structures are physically and functionally connected forms the basis of clinical symptoms and signs.   Examination of the brain is carried out by examining the sensory organs and muscles. Consider a patient brought to the Emergency Room by a family member with a chief complaint of  expressive aphasia (inability to express), also called Broca’s aphasia .  “We were eating dinner and suddenly he had difficulty speaking.  He seems to know and understand what I am saying but he cannot express himself” she explains.  Acute onset expressive aphasia usually occurs as a result of a stroke or a vascular accident (often thrombosis) in a branch of the middle cerebral artery that supplies the dominant hemisphere of the brain (left brain for dominant right handed people).  The involved artery supplies the insula and frontoparietal operculum.  The physician should immediately take a look at the patients face. The muscles of the face are controlled by inferior frontal gyrus, and a droop of the facial muscles, best seen as a droop of the right upper lip places the disease in the inferior frontal branch of the middle cerebral artery.   The experienced physician greets the patient with a warm smile and may elicit a return smile, at which time this droop is more easily appreciated.  Extending a hand to the patient for a handshake may reveal weakness in the hand or upper limb. The art of medicine is invoked in a warm and non provocative way by connecting the presenting problem with its relevant connections in the patient’s nervous system.  In addition, appropriate diagnostic connections and actions are invoked in the thought processes and actions of the physician.  The senses of the physician should be bristling all the time, with eyes and ears open to all and any clues, and reactions that are connected, integrated, respectful, kind, thoughtful and meaningful.

The Pulse

Examining the pulse, with its direct connection to the heart is another obvious example where the examination of one structure is truly the examination of a second connected structure.  The pulse has a history based in ancient medicine.  The Yellow Emperor Huang Ti of China (2698-2598 BC) understood that the pulse could be influenced by emotion. It is palpated with three fingers, and its evaluation was considered an art form linking it to the heart, kidney and liver.  The finger that assesses the pulse closest to the hand connects to the heart, while the middle part of the pulse relates to connection with the liver, and the most proximal to the kidney.

Hippocrates (460-370BC), the father of medicine introduced the concept of clinical inspection and observation. He was known to take the pulse of the patient while taking a history, but did not elucidate any overt connections.  According to Vesalius, Herophilus of Chalcedon (about 280BC) had major influence on the use of the pulse to diagnose disease, and made the observation that the pulse was not an innate characteristic of the arteries but was related to the heart.

There is a touching story of the pulse of a young lustful man, had relevance in history.  Erasistratus from Ioulis (about 310-250BC) served as court physician to King Seleucus I who was one of Alexander the Great’s commanders and a founder of the Seleucid dynasty.  King Seleucus had married a young and beautiful princess named Stratonice.  After the marriage the king’s son Antiochus fell ill and Erasistratus was asked to determine the cause of the disease.  Erasistratus noted that the pulse of the young prince (among other symptoms of passion) accelerated every time the beautiful princess, wife of his father, walked into the room.  Erasistratus cleverly and kindly explained to King Seleucus the of the cause of his son’s malady and the malady was solved by the king giving up his wife and his kingdom of all the provinces of upper east Asia to his son. Plutarch’s commentary on the event is a marvel to read, and a painting by Jacques-Louis David, 1774 “Erasistratus Discovering the Cause of Antiochus’ Disease” is equally enthralling to behold.

A similar story is told about Galen (130- 200AD)  (William Osler – The Evolution of Modern Medicine see who was summoned to evaluate a young woman who suffered from profound malaise.  On examination by Galen there was neither fever nor change in her pulse.  While he was chatting with her, with his finger on her pulse, he noted that her rate increased and became irregular when the conversation drifted to an actor called Pylades.  He concluded that she was suffering the same malady as Antiochus, son of King Seleucus.

Both these stories describe the connections of the mind, the autonomic nervous system, the heart and the pulse.

Galen wrote 18 books on the pulse. Connecting disease with the pulse, he described a “pulsus celer”, collapsing pulse indicating a wide pulse pressure, due perhaps to aortic regurgitation or perhaps high output failure, and “pulsus tardus”,  a slow rising pulse, indicating  perhaps aortic stenosis.  Other colorful examples include pulsus myurus (like a rats tail), pulsus caprizans with a double impulse, (like the leap of a goat), and pulsus formicans resembling the movement of an ant, indicating the weak and thready pulse of hypotension.  (Fleming)

The modern examination of the pulse has been enhanced and advanced by application of the sphygmomanometer, pressure transducers, and echocardiography.  These devices are routinely used to assess heart disease, and are far more accurate than palpation. Unfortunately they have superseded the art of pulse examination at the bedside. However, when faced with an acute situation, such as a person suddenly dropping to the ground, evaluation of the pulse is a rapid, useful, and sometimes lifesaving diagnostic maneuver.  Basic CPR demands an ABC approach:  Airway, Breathing, and Circulation.  The Circulation is assessed by feeling the pulse, and evaluation of the pulse will determine the next step.  A slow pulse, commonly implies a vagal reaction, or faint, and is often associated with pallor, sweatiness, and a complaint prior of nausea and dizziness or faintness.  In this instance the findings connect to an excess parasympathetic tone, or vagal reaction, also called a vasovagal reaction.  This reaction slows  the heart and also causes the veins to dilate, so insufficient blood returns to the heart which is already slowing.  The circulation becomes insufficient, and the patient faints due to lack of sufficient blood flow to the brain.   The first step is to lay the person down so that the blood does not have an additional uphill battle to get to its destination.  The second is to elevate the legs in order to empty the dilated veins of the pooled blood and return it to the heart, so there is more available for the heart to pump into the brain.   The return to a normal heart rate is accompanied by improvement in the patient’s symptoms.

If on the other hand, no pulse is felt when a patient suddenly collapses, then cardiac arrest is diagnosed, meaning an abrupt failure of pump function.  The most common cause includes ventricular fibrillation and ventricular tachycardia, which are responsive to defibrillation.  Other causes are less common and include asystole and pulseless electrical activity, which are not responsive to defibrillation.

The fact that the heart is connected to the arteries, allows the clinician to examine the pulse, and gain insight into the health of the heart. In early times this connection was not understood.  Today it is involved in basic lifesaving techniques.

Connections and connectedness are essential to biological structure. Bonds and bonding in the molecular environment are elemental and extend through all of biology and society.  The pathological equivalent of disconnectedness ranges from the simple to the complex.  Disconnectedness in the clinical world may be congenital or acquired.  Transposition of the aorta is a congenital abnormality where the aorta is connected to the wrong ventricle.  Survival is impossible if the disorder is not surgically corrected.  Acquired disconnectedness occurs in easily treated traumatic dislocation of a joint, but can be life threatening in traumatic rupture of the aorta.  Loss of connections to society occurs to many unfortunate individuals and societal awareness to this problem needs to be heightened.  Biology depends on strong and meaningful connections.


At the Cellular Level


Organs Connecting

People Connecting

Spines Bonding – Nerves on Edge
46570c05.800 man woman lovers spine backbone 

Ashley Davidoff MD


The Wedding  – The Family
A large family wedding with 12 children. Note the complexion of the groom is completely different to bride’s and her family. Genetics goes deeper than we know, and the good and the bad surface  intermittently. However there is no telling when this will occur or become phenotypic.


Ashley Davidoff MD

The red sweats – the motto on the shirt “You ‘re here- there’s nothing I fear” – 82084pb01.800

Ashley Davidoff MD

71216.800 soccer team people uniform link connections unity united 

Ashley Davidoff MD

Bonding in Defense of Rights
84015p.800 Lincoln Massachusetts Minuteman State Park Reenactment of the days of the Revolution America circa 1775 army link connections bonds defense offence war men army gun horses Boston 

Ashley Davidoff MD

Other Biological Units Connecting

Other Units Connecting 

Ashley Davidoff MD

A Farm – Links to The Earth – Mountains Farms and Walls in Peru

0178.800 Peru farm wall units to unity mountains vertical agriculture food the common vein applied biology 

Ashley Davidoff MD

Highways Byways and Waterways for the City
32165 code RS pulmonary lung alveolus arteriole venule epithelium drawing gas exchange anatomy physiology histology83557.800 highways waterways reservoirs storage stations factories homes transport systems bus cars 

Ashley Davidoff MD

System of Wires Nerves and Autonomic Ganglia
In this scene of Johannesburg taken from the highway, we can view the vital lines of electrical energy that are essential to maintain the city. In the distance we see the city that the electrical lines serves.  We also see other elements that have biological equivalents.  – the fence that protects and prevents and forms a border between the highway and the property of the homes that reside on the other side.  An old goldmine dump to the left of the picture – the tall post office tower for communication and a host of office buildings for collaborative effort. 57692 city electricity air energy essential community need Johannesburg South Africa fence capsule tcv the common vein Davidoff photography

83925 electricity node ganglion nerve control telephone cable box

Ashley Davidoff MD

Links and Connections in Disease

Disease of One Causes Disease of the Other

Chronic Infarction Right Temporal Lobe and Right Occipital Lobe

– atrophy of the brain leads to a pull on the ventricles

71419c01.800 74 female with h/o ataxia incontinence memory loss brain cerebrum right PCA territory right posterior cerebral artery posteromedial aspect of right temporal lobe medial and inferior aspect of the right occipital lobe gliosis volume loss atrophy ex vacuo changes dilatation of temporal and occipital horns of the lateral ventricles dx old chronic infarction CTscan MRI a = Ctscan b = DWI c= sagittal T1 weighted d – T2 weighted e = FLAIR f = FLAIR coronal 

Ashley Davidoff MD

An Obvious Dislocation

No Subtleties about this One 

Following a fall this young patient has an obvious dislocation of the elbow joint.  A dislocation reflects an abnormal position as well as an aberrant connection or link between the three structures – humerus, radius and ulna.

aberrant connection72041.800 elbow bone olecronon fracture humerus ulna radius fx dislocation position trauma plain X-ray

Ashley Davidoff MD

Links and Connections in Biology

The Common Vein Copyright 2007

The human body is an exceedingly complex structure – a masterpiece of intricacies constructed from simple biological and chemical units.  However, its functional integrity would be highly compromised without the vast series of structural and chemical links that connect its cells, tissues, and organs.  In this way, the concept of links and connections underlies biology and medicine and is critical to the work of a physician.

The interdependence of biological structural units first takes form at the atomic level with a variety of bonding interactions, including covalent and ionic bonds.  Covalent bonds, which arise from electron-sharing between two atoms, are easily distinguished from ionic bonds, which require electrostatic attractive forces between two oppositely charged ions.  Both types of bonds are actually the result of a careful balancing act, as the positive nuclei of the two atoms experience repulsive forces.  In fact, such electrostatic forces must be continually considered as one progresses up the ladder of structural complexity toward intermolecular interactions and the formation of compounds.

Positive and Negative
84154b04.698 positive and negative extreme states black and white
Ashley Davidoff MD

Having risen above the atomic and molecular levels one may next consider the cell, which is the fundamental unit of biological structures.  Incidentally, it is also the site of myriad linkages, as connections between organelles like the endoplasmic reticulum and Golgi apparatus allow the cell’s system of transport and packaging to take form.  In this way, one sees the first example of links and connections as critical for establishing structures of particular function within an organism.

Bonds Links Connections Atoms Molecules
70983.800 molecules atoms bonds links connections relations collage Ashley Davidoff art
Intestinal Epithelial Cell – Golgi Apparatus and Intercellular Borders
71798b13b03.800 cell endoplasmic reticulum mitochondria fat droplet absorption by microvilli processing cisterna interdigitation of cells pinocytic vesicle intercellular space function absorption Davidoff art Ashley Davidoff MD

At the Cellular Level

John Donne a clergyman and poet from the renaissance period stated that “… No man is an island …”  In the same way no cell, organ, body or community is an island.  Each is connected and dependent on the other members of the society in which they live.  They are connected both structurally and functionally. 

While such intracellular connections are of great import, the linkages between individual cells must also be considered, as they allow for the formation of tissues and organs with distinct functional characteristics.  Two examples of such connections are shown below.

Positioning of Liver Cells in Cords – Reticulin Bond                                                                                     Cells are Linked by Reticulin Connective Tissue and Conduit Vessels Nerves and Chemicals      The cells of the liver are organized in cords and plates and are organized like spokes of a wheel  around the central vein. The plates and cords are lined by the sinusoids which are the channels which carry blood to the liver.  Just below the sinusoids, between the wall of the sinusoid and the capsule of the liver there is a space called the space of Disse which carries the lymphatic fluid of the liver.   (Image courtesy of Barbara Banner M.D.) 13236
13236 liver hepatocyte liver cords sinusoids cytoplasmic granules connective tissue reticulin histopathology histology Courtesy Barbara Banner MD
Holding the Lung Cells Together
Normal lung-  Lower magnification Note cup-shaped alveolar spaces outlined by delicate thin alveolar capillary membrane.                             
Courtesy Armando Fraire MD. 32819 keywords lung pulmonary normal alveolus alveoli histology interstitium interstitial
Cardiac Syncitium
A drawing of the histology of the myofibrils of the heart showing how they ae connected and related as a continuum enabling a coordinated contraction pattern. Courtesy Ashley Davidoff MD. 32907 code cardiac heart muscle syncitium histology Ashley Davidoff art

The manifestation of these intercellular associations is the development of progressively greater, more complex structures, as tissues interact to form distinct organs.  The image below, for instance, depicts this type of interaction, as solid plates of bone are joined to each other at the coronal and sagittal sutures, allowing the skull to take form.

Link between Liver Lobule and the Body
– The Hepatic Vein
13009 W I 13 liver + portal triad lobule + anatomy histology portal vein bile duct hepatic artery central vein hepatic vein
Ashley Davidoff
Bonds Cement Bridges Joints Interstitium Connective Tissue Ligaments Sutures Vessels
Skin and Muscle of the Buttock
Note the linear and parallel orientation of the muscle fibers of the gluteus muscles (charcoal) and the reticular pattern of the connective tissue of the skin of the buttock (light gray)
keywords skin muscle gluteus buttock folds skin interstitium connective tissue vessels links bonds connections MRI coronal view
Ashley Davidoff MD

From Head to Toe

The highly varied array of organs within the body allows for great multiplicity of function within an organism.  However, the value of such diversity would be negated without the system of linkages that allows the organs to communicate with one another.  This system consists of both structural connections, such as the network of tubules shown below, and chemical links established and maintained by the endocrine and exocrine systems of the body.

Tubular Links between the Organs
32369 tube colon small bowel lung bronchus bronchi esophagus stomach large bowel bile duct ureter brain liver urinary bladder heart cardiac artery arteries arterial system veins venous system tube principles Davidoff art Courtesy Ashley Davidoff MD
From Head – Coronal Suture – Starting at the Top
46304b01 bone skull suture shape CTscan 
Ashley Davidoff MD
Pituitary Gland – Connecting the Body through Hormones
14798 04.800 brain pituitary anatomy normal Ashley Davidoff art
Arterial Connections to Brain Cells
46352b19.800 head brain blood supply internal carotid artery branches circle of Willis MRA 3D TOF Davidoff MD normal anatomy tree of knowledge 
Ashley Davidoff MD

 Vessels Nerves and Lymphatics – The Cables

Cardiovascular System
32368b05.800 cardiovascular system heart cardiac artery arteries capillary capillaries arterioles venules veins negative firces positive forces road highway TCV the common vein applied biology
Ashley Davidoff MD
Aorta Renal Arteries Iliacs and Lumbar Arteries
Ashley Davidoff MD
Veins From the Tip of the Fingers to the Tip of the Toes – Connected
10392.800 vein arm basilic valve
Ashley Davidoff MD
Veins and Valves
26032d.800 vein tube valve flow normal anatomy 
Ashley Davidoff MD


The Nerves – Cauda Equina
46523.800 spinal cord cauda equina nerves anatomy applied biology normal
Ashley Davidoff MD


Junction of Bile Duct with Duodenum at the Papilla
71731.800 bile duct duodenum papilla valvulae conniventes small bowel common bile duct CBD CHD common hepatic duct links connections tubes cystic duct remnant normal biology anatomy intraoperative cholangiogram following cholecystectomy Ashley Davidoff MD

In this way, by visualizing the linking of atoms to form molecules to form compounds to form cells, tissues, organs, and the human body, one realizes the potency of links and connections as embodiments of the “units to unity” concept.  Furthermore, they are the means by which human relationships form, as one organism interacts with many others to form couples, families, and communities.  The theme may even be extended to the structure of our cities and towns, as elaborate networks of roads are established to facilitate the human interactions described above.  Links and connections, then, represent a concept at the very heart of our existence.

Gastrointestinal Tract  – Esophagus to Stomach to Small Bowel to Colon One Long Tube
60641 abdomen small bowel ileum jejunum portal vein normal anatomy TCV applied biology volume rendering CTscan Ashley Davidoff MD


Bones Connecting and Linking- Protection
49640 bone rib thoracic spine spinous processes scapula protection support CTscan volume rendering 
Ashley Davidoff MD
To Toes – The Phalangeal Joints
46712b01 bone foot feet phalanges interphalangeal joints metatarsophalangeal joints normal anatomy applied biology X-ray plain film 
Ashley Davidoff MD
Ligaments and Tendons
Ashley Davidoff MD
Spines Bonding – Nerves on Edge
46570c05.800 man woman lovers spine backbone 
Ashley Davidoff MD
56889 fish processors in Portugal young women uniform gum boots TCV the common Vein Davidoff photography Ashley Davidoff MD
Highways Byways and Waterways for the City
Note the Bunker Hill monument in the far right of the image- Importance of linking to our heritage and history83557.800 highways waterways reservoirs storage stations factories homes transport systems bus cars Ashley Davidoff photography
Prior Link to all Life
49703b17c01.801 body in 12 moods umbilicus abdomen a day in the life a year in the life Ashley Davidoff art
Connections through the Roots
This group of pine trees share space sun and water. They share the seasons. Usually not seen and not heard are their roots which share sustenance from the earth and they health and growth is dependent on this as well. The roots of the first two trees are intermittently connected and linked as can be seen by the first pair of trees whose roots can be seen growing toward each other. they are of course in competition but they have learned to live share, and combine with other trees to form a forest which in the end is bigger and more powerful than the individual parts. Mason Rice School park trees links and connections share bond roots sun environment Davidoff photography Ashley Davidoff art 91016p.8s
Links in the Chain
The monkey bars are connected to a chain and the chain is connected top a wooden frame. In this case the functionality of the toy is dependent on the strength of the connections and bonds. The tree and the bushes in the background are of course dependent on the their roots to connect them to the ground and nutrition and the branches are connected to the atmosphere and the sun. links and connections monkey bars units to unity sphere half two halves make the whole Davidoff photography Ashley Davidoff art 90997p.8k.8s


Quantum Theory and Connections

Quantum theory thus reveals a basic oneness of the universe. It shows that we cannot decompose the world into independently existing smallest units. As we penetrate into matter, nature does not show us any isolated “building blocks,” but rather appears as a complicated web of relations between the various parts of the whole. These relations always include the observer in an essential way. The human observer constitute the final link in the chain of observational processes, and the properties of any atomic object can be understood only in terms of the object’s interaction with the observer.

Fritjof Capra

In The Tao of Physics (1975), 68.

Oneness for Other Reasons

Quantum theory thus reveals a basic oneness of the universe. It shows that we cannot decompose the world into independently existing smallest units. As we penetrate into matter, nature does not show us any isolated “building blocks,” but rather appears as a complicated web of relations between the various parts of the whole. These relations always include the observer in an essential way. The human observer constitute the final link in the chain of observational processes, and the properties of any atomic object can be understood only in terms of the object’s interaction with the observer.

 Fritjof Capra

In The Tao of Physics (1975), 68.

Interactions and Connections

We have now got what seems to be definite proof that an X ray which spreads out in a spherical form from a source as a wave through the aether can when it meets an atom collect up all its energy from all round and concentrate it on the atom. It is as if when a circular wave on water met an obstacle, the wave were all suddenly to travel round the circle and disappear all round and concentrate its energy on attacking the obstacle. Mechanically of course this is absurd, but mechanics have in this direction been for some time a broken reed.

Henry Moseley

Letter to Margery Moseley (2 Feb 1913). In J. L. Heilbron (ed.), H. G. J. Moseley:

The Life and Letters of an English Physicist 1887-1915 (1974), 201.

Atoms and Organic Molecules

We set out, therefore, with the supposition that an organised body is not produced by a fundamental power which is guided in its operation by a definite idea, but is developed, according to blind laws of necessity, by powers which, like those of inorganic nature, are established by the very existence of matter. As the elementary materials of organic nature are not different from those of the inorganic kingdom, the source of the organic phenomena can only reside in another combination of these materials, whether it be in a peculiar mode of union of the elementary atoms to form atoms of the second order, or in the arrangement of these conglomerate molecules when forming either the separate morphological elementary parts of organisms, or an entire organism.

Theodor Schwann

Mikroskopische Untersuchungen über die Uebereinstimmung in der Struktur und dem Wachsthum der Thiere und Pflanzen (1839). Microscopic Researches into the Accordance in the Structure and Growth of Animals and Plants, trans. Henry Smith (1847), 190-1

Linking and Bonding Atoms and Molecules

[The] structural theory is of extreme simplicity. It assumes that the molecule is held together by links between one atom and the next: that every kind of atom can form a definite small number of such links: that these can be single, double or triple: that the groups may take up any position possible by rotation round the line of a single but not round that of a double link: finally that with all the elements of the first short period [of the periodic table], and with many others as well, the angles between the valencies are approximately those formed by joining the centre of a regular tetrahedron to its angular points. No assumption whatever is made as to the mechanism of the linkage. Through the whole development of organic chemistry this theory has always proved capable of providing a different structure for every different compound that can be isolated. Among the hundreds of thousands of known substances, there are never more isomeric forms than the theory permits.

Nevil Vincent Sidgwick

Presidential Address to the Chemical Society (16 Apr 1936), Journal of the Chemical Society (1936), 533.

The Electron and Its Behaviour or Misbehaviour

…where the electron behaves and misbehaves as it will,

where the forces tie themselves up into knots of atoms

and come united…

D.H. Lawrence

‘Give Us Gods’, David Herbert Lawrence, The Works of D.H. Lawrence (1994), 354.