Jean-Antoine Nollet discovered that membranes could be selectively permeable and analyzed the process by which a solvent concentrated on one side of such a membrane would pass through it until an equilibrium on either side of the membrane had been reached. Henri Dutrochet later related this process specifically to biological systems and gave it the name “osmosis.”

It is a well-known principle that nature abhors a vacuum. Nature;abhors a vacuum
Vacuum, nature’s abhorence of[Vacuum, natures] A gaseous or liquid substance concentrated in one portion of a space will tend to spread out until it is evenly distributed, thereby filling “vacuums,” or areas that had been devoid of the substance. This process is known as diffusion. Diffusion Osmosis is a particular kind of diffusion. [kw]Nollet Discovers Osmosis (1748)
[kw]Osmosis, Nollet Discovers (1748)
[kw]Discovers Osmosis, Nollet (1748)
Osmosis
[g]France;1748: Nollet Discovers Osmosis[1250]
[c]Chemistry;1748: Nollet Discovers Osmosis[1250]
[c]Science and technology;1748: Nollet Discovers Osmosis[1250]
Nollet, Jean-Antoine
Franklin, Benjamin
[p]Franklin, Benjamin;lightning rods
Dutrochet, Henri
Pfeffer, Wilhelm
Van’t Hoff, Jacobus Henricus

The process of osmosis involves a semipermeable membrane, Membranes and osmosis that is, a barrier that can be penetrated by some substances but not by others. Osmosis occurs when a solvent diffuses across such a membrane. So, for example, if pure water is placed on one side of a semipermeable membrane and salt water is placed on the other side, the pure water will flow through the membrane, diluting the salt water. On the other hand, if there are equal concentrations of salt in the water on either side of the membrane, the equilibrium of the two solutions will prevent the water from diffusing through the membrane. Osmosis is a crucial process in biological cells Cellular biology and complex organisms. Organic chemistry It is one of the means through which plants and animals regulate their internal chemistry, and it drives other processes necessary to the health of those organisms. The first examples of osmosis to be observed in a laboratory were observed by Jean-Antoine Nollet.

Nollet was born into a peasant family on November 19, 1700, in Pimpré, Oise, France. After training for the priesthood, Nollet was appointed to a deaconship (1728) and eventually served as abbé (abbot) of the Grand Convent of the Carthusians in Paris. Though trained primarily in theology and maintaining a strong religious conviction throughout his life, Abbé Nollet is better known for his work in experimental physics. He was a member of both the Royal Society Royal Society, England of London, to which he was admitted in 1735, and the French Académie des Sciences (Academy of Sciences), Academy of Sciences, France of which he first became an associate member in 1742. He was appointed professor of experimental physics at the University of Paris. Nollet was also sought after by royalty: He provided scientific services to the duke of Savoy in Turin, Italy, and he served as physics teacher to the royal children at the court of France’s Louis XV.

Much of Nollet’s work centered on the question of the nature of electricity. Electricity;nature of Nollet viewed electricity as a flow of matter taking place between charged bodies. In 1748, he invented the electrometer, Electrometer an instrument capable of detecting and measuring electric charges. Nollet also demonstrated the flow of electricity in a form of parlor trick: He caused an electric charge to pass through a row of men, making them all jump simultaneously.

Nollet adapted his interest in electrical flow to crude experimentation in biological systems. He was aware of German experiments observing the effects of electricity on the flow of water. Water in a thin capillary tube would simply drip from the open end. However, if electricity was applied to the tube, the water would flow in a constant stream. Nollet began a series of experiments in which he measured the rate of water transpiration in plants and animals as a function of the presence or absence of electricity. He noted an increase in the transpiration rate when the organism was electrified.

Nollet’s religious views, as well as the questions dealing with the nature of electricity, later became the basis for conflict with the American statesman and naturalist Benjamin Franklin. During the 1740’s, Franklin began a series of experiments addressing the question of the nature of electricity, culminating with recognition of what became the concept of conservation of charge. During the summer of 1752, Franklin carried out his famous kite experiment, demonstrating that lightning was a form of electricity. Electricity;and lightning[lightning] The immediate application of this work was his invention of the lightning rod, Lightning;rods a device to protect buildings from fire resulting from lightning strikes.

Nollet, likely jealous of an “amateur’s” discovery or possibly as a result of the zealotry of his religious views, argued that the lightning rod was an “offense to God.” Nollet’s argument was based on the idea that lightning originated from the heavens, and that by interfering with an instrument of God, one was in effect carrying out an offense against him. Though the lightning rod was quickly adopted through both Europe and the rest of the Western world, the controversy did result in harsh words between Nollet and Franklin. Ironically, it was Nollet’s observations that led to lightning rods being given their modern form: presence points on the ends of electrical conductors.

In 1748, Nollet carried out the experiments in which he discovered what is now known as the principle of osmosis. Nollet prepared a vessel containing alcohol (“spirits of wine”) and enclosed the vessel within a piece of pig’s bladder. After placing the covered vessel into a larger container filled with water, Nollet observed that, while the water traversed the bladder wall, the alcohol would remain trapped within the bladder. In some experiments, the bladder would expand until it burst. In addition to the principle of osmosis itself, Nollet had demonstrated the semipermeability of the bladder wall, although that term would not be invented for 150 years.

Nollet’s work was carried out against the background of the Enlightenment. Enlightenment;Europe Prior to this period, science remained dominated by the classical views that had been held since antiquity; in no small part, this was the result of the continued influence of the Church. In the eighteenth century, however, the beliefs of antiquity came to be questioned as argument from authority was replaced by scientific methodologies, experimentation, and the use of evidence to prove one’s beliefs, in philosophy no less than in physics. It was the age of Voltaire as much as that of Thomas Jefferson. The evolution of scientific experimentation represented merely one portion of the changes occurring throughout Europe.

In the early decades of the nineteenth century, Nollet’s countryman Henri Dutrochet became aware of Nollet’s work and attempted to apply the same principle to the movement of fluids across cell membranes. While studying both plant and animal cells with a microscope, Dutrochet observed the movement of water as a solvent through the cell membrane, a process he termed osmosis. Dutrochet further observed that the direction of a solvent’s flow was determined by the nature of the solvent rather than by the nature of the membrane. The solvent would always flow from a weaker, or less concentrated, solution into a stronger, or more concentrated, solution of a given solute.

Dutrochet tested his ideas by building an osmometer, Osmometers an instrument capable of measuring the movement of water across an artificial barrier. Dutrochet referred to the movement of water across the barrier as “endosmosis,” while the reverse movement was termed “exosmosis.” The idea of the cell membrane as a barrier capable of regulating osmosis was then inimical to cell theory; it was certainly beyond Nollet’s ability to apply to biology in any meaningful way. Nevertheless, Nollet’s discovery represented one of the first in the developing area of experimental physics, and it would become crucial to correcting and refining cell theory.

Once a similar process was found to occur in conjunction with biological membranes, moreover, applications in several scientific fields quickly developed. German botanist Wilhelm Pfeffer, for example, explained a role for osmotic pressure in the action of fluids within plant vessels. The mathematics of osmosis and chemical equilibrium were worked out by Dutch chemist Jacobus Henricus van’t Hoff. As a result, he was awarded the first Nobel Prize in Chemistry in 1901. It was van’t Hoff who coined the term “semipermeable” to describe the selective penetrability of cellular membranes.

• Franklin, Benjamin. Autobiography of Benjamin Franklin. New York: Buccaneer Books, 1984. Franklin discusses the controversy that arose between him and Nollet on the subject of electricity.
• Gay, Peter. The Enlightenment: The Science of Freedom. New York: W. W. Norton, 1996. The development of what became known as science against the background of the Enlightenment. Nollet only has a brief mention, but the context of his work is apparent.
• Isaacson, Walter. Benjamin Franklin: An American Life. New York: Simon & Schuster, 2003. Biography of Franklin that includes information about the controversy between his work on electricity and Nollet’s religious views.
• Kirkham, M. B. Principles of Soil and Plant Water Relations. St. Louis, Mo.: Elsevier, 2005. Principles of water movement in plants, the result of osmotic pressure originally described by Nollet.
• Mason, E.A. “From Pig Bladders and Cracked Jars to Polysulfones: An Historical Perspective on Membrane Transport.” Journal of Membrane Science 60 (1991): 125-145. A history of the science of membrane transport, beginning with Nollet’s observations with a pig bladder.
• Tompkins, Peter, and Christopher Bird. The Secret Life of Plants. New York: Harper & Row, 1973. This classic provides a rather anthropomorphic view of plants as “beings.” Included is some background behind Nollet’s initial work on the movement of water in the presence of an electric field, as well as the influence of electricity on seed germination.

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Benjamin Franklin; Thomas Jefferson; Louis XV; Voltaire. Osmosis