Red corpuscle of blood

The blood is a complex organ that circulates cells and nutrients throughout the body. One important function of the blood is carrying oxygen from the lungs to the various cells and tissues throughout the body.

In the 1490s, Leonardo da Vinci wrote that the circulatory system is ‘a tree of veins’. He also stated that: All the veins and arteries arise from the heart.

Knowledge of the nature of blood was advanced by the work of Jan Swammerdam (1637-1680), a Dutch experimenter with microscope.

Swammerdam studied at Leiden University, completing a degree in medicine at age 30, with a dissertation on human breathing.

In about 1658 he was the first to describe the red corpuscles of blood from a microscope inspection of the blood of frogs.  Swammerdam described about red blood corpuscles in his famous Bibiia Naturae which was published only in 1738 by Boerhaave, many years after the author’s death in 1680.

Unaware of this work, Anton van Leeuwenhoek provided another microscopic description in 1674, this time providing a more precise description of red blood cells, even approximating their size. He estimated their size to be, in modern terminology, 8.5 microns in diameter (the correct value is 7.7 microns).

Leeuwenhoek found that red blood corpuscles settled at the bottom when sedimented and would lyse when water was added.

In 1901 Karl Landsteiner published his discovery of the three main blood groups – A, B and C (which he later renamed to O).
Red corpuscle of blood

Discovery of oxygen

Arising from the earlier entities of phlogiston and combustible air, oxygen was the product of several interconnected and near simultaneously discoveries in the 1770s by scientists working in three different countries: Carl Wilhelm Scheele, Joseph Priestly and Antoine-Laurent- Lavoisier.

Oxygen was first discovered by Carl Wilhelm Scheele, as Swedish chemist in 1772. However, he did not publish his observations until 1777.

In the meantime, Joseph Priestly, and English chemist independently discovered oxygen in 1775 and published his findings that same year. But it was Antoine-Laurent- Lavoisier who not only helped to discover the element but is also credited with naming it ‘oxygen’.

Antoine-Laurent- Lavoisier

With personal fortune and the help of his wife, Marie-Anne-Pierette Paulze, Lavoisier experimented on respiration, combustion and oxygen. By 1777 he had formulated a chemical theory of life as a process of oxidation.

Hemoglobin was identified as the ‘red pigment’ in the globules in 1851 by the German physiologist Otto Funke. His compatriot, Felix Hoppe-Seyler, professor of applied chemistry at Tubingen proved that the pigment could take up and discharge oxygen. It was him who called the blood pigment ‘hemoglobin’ in 1862.

He found that oxygen loosely bonds to hemoglobin to form oxyhemoglobin, which can give up its oxygen to the tissue in the body.

Paul Bert, a French physician measured the oxygen of arterial blood samples and related them to  the ambient pressure; in 1872 he was the first to publish graphs relating the two variables, pressure and content or saturation, later termed the oxygen dissociation curve.

In 1931, Ludwig Nicolai initiated the quantitative spectrophotometric investigation of light transmitted through human skin in an effort to understand the dynamics of tissue oxygen consumption.
Discovery of oxygen

History of leukocytes

In 1843, ‘white globules’ were identified in the blood simultaneously by Gabriel Andral and William Addison, and shown to be associated with disease.

Addison, recognized pus cells as being blood cells that had passed out of the circulation to the site of infection. Addison, a physician of Malvern, England reported that leukocytes moved from the circulation into the tissues and that this movement increased during inflammation.

The emigration of leukocytes from blood into tissues was observed by Augustus Waller and by Addison in the early part of the 19th century and Schultz first described phagocytosis by human leukocytes in 1865. 

Shultz z also was the first reported that white blood cell were not a uniform class of cells, but have different shapes.

Thomas Wharton Jones, a London eye surgeon and physiologist in 1847 reported for the first time the amoeboid movement of leukocytes.

Leukemia was described in the intervening years but it was 1879 before Paul Ehrlich published his method for staining blood films. Paul Ehrlich, Nobel Prize winner is credited with the first description of the human basophil in 1879.

This was the birth of the blood ‘differential’ and the recognition that leukocytes are in some way associated with infectious disease.

The discovery of eosinophil, basophils and other types of cells came a bit later on the early part of the 20th century with the widespread use of blue and red dyes – hematoxylin to stain nuclei and eosin to stain cytoplasm.
History of leukocytes

Discovery of hemoglobin

During the 19th and early 20th century a number of protein crystals were observed in animal and plant cells under the light microscope.

The first description of oxygen-carrying protein hemoglobin is attributed to work on earthworm blood by F. L Hünefeld in 1840. He accidentally creates the first protein crystals of hemoglobin.

By the time Wilhelm Preyer wrote his book Blood Crystals in 1871, hemoglobin crystals from over forty species of mammals, fishes, birds and amphibians has been described.

A 1909 book entitles The Crystallography of Hemoglobins, by physiologist Edward Reichert and Thomas Brown reproduced 600 photomicrographs of hemoglobin crystals from a hundred different species. 

Physiologists and medical chemists in the late nineteenth century devoted an immense amount of research to hemoglobin. A major advanced came in 1904 when Christian Bohr, Karl Hasselbalch and August Krogh discovered the binding oxygen hemoglobin.

In 1954, Max Perutz discovers that soaking protein crystals in heavy atoms will provide information needed to turn diffraction patterns into structural pictures of proteins.

In 1959 he determined the molecular structure of myoglobin (similar to hemoglobin) by X-ray crystallography. Before that John Kendrew obtains the first high-resolution three-dimensional structure of a protein myoglobin.

This work resulted in Max Perutz sharing with John Kendrew the 1962 Nobel Prize in Chemistry.

The role of hemoglobin in the blood was elucidated by French physiologist Claude Bernard.

Other recent discovery is the role hemoglobin plays in blood pressure regulation. Hemoglobin attaches to nitric oxide gas and transports it to and from tissues. Nitric oxide produces vasodilation.
Discovery of hemoglobin

Nutritional Anemia in history

The term nutritional anemia refers to a decreased concentration of hemoglobin or a decreased number of red blood cells in the blood that results from the lack of a substance obtained and replenished by ingestion of food stuffs.

Iron, vitamin B12 and folic acid are the primarily requirements for hemoglobin formation. An early study on the composition of blood was conducted by Robert Boyle in 1864.

Vincenzo Mengini a chemist and physician in Italy, demonstrated in 1747 that particles of dried, powdered blood were attracted to a lodestone, suggesting the existence of iron in blood.

The relationship among hookworm infection, iron deficiency and poor growth an cognition in children were describe in the 19th century and early part of the 20th century.

In 1824, James Scarth Combe described a pernicious anemia, a fatal nutritional anemia and suggested it could be related to a disorder of the digestive tract.

The understanding toward the etiology of pernicious anemia did not come until 1926 when George Minot and William Murphy, physician from Boston found that lightly cooked liver, which the prominent hematologist G. H Whipple had found to accelerate the regeneration of blood in dogs made anemic by exsanguinations, was highly effective as therapy for the disease.

Whipple, Minot and Murphy received the Nobel Prize in Physiology or Medicine in 1934 for their discovery that liver treated pernicious anemia.
Nutritional Anemia in history

Discovery of red Blood Cells

Jan Swammerdam (1637-1680) in Amsterdam first identified red cells with a light microscope and he described them as ‘ruddy globules’.

As early as 1658 he described them in the blood of the frog, but his observations were not published till fifty-seven years after his death by Boerhaave. It was published in Biblia Naturae in 1738.

In 1661, Marcellus Malpighi observed the red blood corpuscles however he failed to recognized their nature mistaking them for fat globules.

In 1674, Anthony van Leeuwenhoek was first recognized red blood corpuscles as the elements responsible for the redness of the blood.

Credit for the discovery of the first cells is given to the English scientist Robert Hooke (1635-1701) who described the microscopic compartments of cork cells in 1665. He was the first person talk about cells.

Throughout the 17th and 18th century naturalist describe a wide variety of cell types, including human cells such as spermatozoa and red blood cells.

Paul Ehrlich (1854-1915) in Silesia, Germany and a pathologist, Rudolf Virchow (1821-1902) from Pomerania, Germany made great contribution in establishing a method for dry smear preparations of blood cells in peripheral blood and staining methods for these blood cells.

In 1897, the Austrian physician Karl Landsteiner discovered that there were four types of blood. He found that humans have four blood types A, B, AB and O.  
Discovery of red Blood Cells

William Harvey and Blood Circulation

William Harvey and Blood Circulation
William Harvey was born in Folkestone, Kent on 1 April 1578. His father was a merchant. Harvey was educated at King's College, Canterbury and then at Cambridge University. The continued his study of medicine at University of Padua.

On his return from Italy in 1602, Harvey established himself as a physician. His career was helped by his marriage to Elizabeth Browne, daughter of Elizabeth I's physician, in 1604. In 1607, he became a fellow of the Royal College of Physicians and, in 1609, was appointed physician to St Bartholomew's Hospital. In 1618, he became physician to Elizabeth's successor James I and to James' son Charles when he became king. Both James and Charles took a close interest in and encouraged Harvey's research.

Harvey's research was furthered through the dissection of animals. While acting as doctor to the court, Harvey carried out lots of research into human biology and physiology. He was very interested in the blood flow in the human body. Most doctors of the time accepted the teachings of Galen and felt that the lungs were responsible for moving the blood around the body but Harvey questioned these beliefs and investigated them scientifically.

Harvey carried out many experiments, both dissections and physiological experiments on animals. His observations of dissected hearts showed that the valves in the heart allowed blood to flow in only one direction. Direct observation of the heartbeat of living animals showed that the ventricles contracted together, dispelling Galen's theory that blood was forced from one ventricle to the other. Dissection of the septum of the heart showed that it contained no gaps or perforations. When Harvey removed the beating heart from a living animal, it continued to beat, thus acting as a pump, not a sucking organ. Harvey also used mathematical data to prove that the blood was not being consumed.

He first revealed his findings at the College of Physicians in 1616, and in 1628 he published his theories in a book entitled 'Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus' ('An Anatomical Study of the Motion of the Heart and of the Blood in Animals'), where he explained how the heart propelled the blood in a circular course through the body. His discovery was received with great interest in England, although it was greeted with some skepticism on the Continent.

Harvey was also the first to suggest that humans and other mammals reproduced via the fertilization of an egg by sperm. It took a further two centuries before a mammalian egg was finally observed, but nonetheless Harvey's theory won credibility during his lifetime.
William Harvey and Blood Circulation