1800
1800
Karl Friedrich Burdach coined the term "biology" to
denote the study of human morphology, physiology and psychology.
1801
Jean Baptiste de Lamarck elaborated a theory of
evolution based on heritable modification of organs through continued use
and loss through disuse.
1802
Gottfried Treviranus and Jean Baptiste de Lamarck
independently broadened the meaning of biology to include the study of all
living things.
1802
Thomas Young proposes a trichromatic theory of color
vision, based on three separate receptor substances in the retina.
1802
Charles Fran?is Brisseau de Mirbel concluded from his
numerous observations of plant structure that "the plant is wholly formed
of a continuous cellular membranous tissue. Plants are made up of cells,
all parts of which are in continuity and form one and the same membranous
tissue."
1804
Nicholas-Th?dore de Saussure published experiments that
represent the first treatment of the subject of photosynthesis using
quantitative methods and modern chemical terminology. He developed the
first balanced equation for the process.
1804
John Dalton enunciated his atomic theory.
1805
Baron Georges Cuvier published his Lesson in Comparative
Anatomy, which introduced that subject.
1805
Ludolf Christian Treviranus asserted that spermatozoa
were analogous to the pollen of plants.
1806
Louis Nicolas Vauquelin and Pierre Jean Robiquet first
isolated an amino acid, asparagine, from asparagus.
1807
B??ict Pr?ost showed that an organism was responsible
for wheat bunt disease.
1809
Jean Baptiste de Lamarck investigated the microscopic
structure of plants and animals. He remarked, "It has been recognized for
a long time that the membranes which form the envelopes of the brain, of
the nerves, of vessels, of all kinds of glands, of viscera, of muscles and
their fibers, and even the skin of the body are in general the productions
of cellular tissue. But no one, so far as I know, has yet perceived that
cellular tissue is the general matrix of all organization and that without
this tissue no living body would be able to exist, nor could it have been
formed."
1809
Jean Baptiste de Lamarck's Philosophie Zoologique
emphasized the fundamental unity of life and the capacity of species to
vary; environmental influences stressed.
1809
Nicolas Fran?is Appert, a French chef, inventor and
bacteriologist, demonstrated a procedure for preservation of foods by
canning.
1810
1810
William Hyde Wollaston isolated the second amino acid,
cystine, from a bladderstone.
1810
Joseph Louis Gay-Lussac deduced the equation for
alcoholic fermentation.
1810
Planche observed that extracts of plant roots would turn
alcoholic solutions of guaiacum blue. The agent responsible for this
change was found to be water-soluble and thermolabile.
1811
Amedo Avogadro proposed that a fixed number of molecules
of any gas will equal the molecular weight of the gas in grams. This was
not widely accepted until 1858.
1811
Charles Bell and Fran?is Magendie discover the functions
of the dorsal and ventral roots of spinal nerves.
c. 1815
Robert Brown distinguished angiosperms from
gymnosperms in his classification of the higher plants.
1815
Konstantin Sigizmundovich (Gottleib Sigismund
Constantin) Kirchhof reported that a glutinous component of wheat is
capable of converting starch to dextrin and sugar.
1815
Jean-Baptiste Biot discovered optical activity.
1817
Christian Heinrich Pander first described the existence
of three germ layers in chick embryos. The concept was later extended by
Karl Ernst von Baer to include all vertebrates.
1817
William Smith's Stratigraphical System of Organized
Fossils showed that certain strata have characteristic series of fossils.
1819
Adelbert de Chamisso introduced the concept of
alternation of generations.
1820
1820
Christian Friedrich Nasse formulated Nasse's law:
hemophilia occurs only in males and is passed on by unaffected females.
1822
John Goss observed segregation of a recessive trait in
peas, but failed to note numerical ratios. In the same year, Alexander
Seton published similar observations.
1822-26
?ienne Geoffrey St. Hilaire experimentally produced
abnormal development in chicks, providing an argument against
preformation.
1823
Thomas Andrew Knight confirmed reports of dominance,
recessivity, and segregation in peas, but did not detect regularities.
1823
Jean-Louis Pr?ost and Jean Baptiste Andr?Dumas showed
that urea is transported by the blood.
1824
Henry Hickman used carbon dioxide to anesthetize
animals prior to surgery.
1824
Henri Dutrochet further advanced the cell principle. He
stated, "All organic tissues are actually globular cells of exceeding
smallness, which appear to be united only by simple adhesive forces; thus
all tissues, all animal (and plant) organs, are actually only a cellular
tissue variously modified. This uniformity of finer structure proves that
organs actually differ among themselves merely in the nature of the
substances contained in the vesicular cells of which they are composed."
1824-25
Jean-Louis Pr?ost and Jean Baptiste Andr?Dumas
repeated Lazarro Spallanzani's filtration experiments, thus confirming the
necessity of spermatozoa for fertilization, and described cleavage in a
frog egg.
1826
Pierre-Jean-Fran?is Turpin reported his observations of
cell division in algae.
1827
Karl Ernst von Baer first demonstrated the mammalian
ovum; he regarded the sperm cells as "Entozoa," i.e., parasites, and named
them spermatozoa.
1828
Publication of Karl Ernst von Baer's The Embryology of
Animals which strongly opposed preformationism.
1828
Friedrich W?ler synthesized the first organic compound
from inorganic components, preparing urea by reacting lead cyanate with
ammonia.
1828
Robert Brown first described Brownian motion.
1828
John Vaughan Thompson first collected and described
plankton. He also correctly described barnacles as crustaceans.
1830
1830
Joseph Lister showed how lenses could be made which
corrected for chromatic and sperical aberration. (This is not the same
Joseph Lister who is known for antiseptic surgery.)
1830
Karl Ernst von Baer enunciated the biogenetic law.
1830
Franz Julius Ferdinand Meyen reported his observations
on algae, fungi and higher plants and concluded that "...each cell forms
an independent, isolated whole; it nourishes itself, builds itself up, and
elaborates raw nutrient materials, which it takes up, into very different
substances and structures."
1830
Pierre-Jean Robiquet and Boutron, also Chalard,
discovered the hydrolytic splitting of amygdalin by an extract of defatted
bitter almonds. The agent was named "emulsin" by Justus von Liebig and
Friedrich W?ler in 1837.
1830
Giovanni Battista Amici investigated the process of
fertilization in plants and was able to trace the growth of the pollen
tube through the style to the micropyle of the ovary.
1830-33
Charles Lyell's Principles of Geology advanced the
theory of uniformitarianism, i.e., the view that geological formations
were explainable in terms of forces and conditions observable at present.
1830-40
Justus von Liebig developed techniques of
quantitative analysis and applied them to biological systems. The idea
that vital activity could be explained in physicochemical terms was an
important one for investigators interested in the nature of life.
1831
Robert Brown published his observations reporting the
discovery and widespread occurrence of nuclei in cells.
1831
Leuchs described the diastatic action of salivary
ptyalin.
1831-1836
The voyage of the Beagle, with Charles Darwin
aboard as naturalist.
1832
Dumortier observed the process of cell division in
algae.
1833-1834
Anselme Payen and Jean-Fran?is Persoz further
described and isolated diastase (amylase) in powder form from barley malt,
showed it to be heat labile, and postulated the central importance of
enzymes in biology.
1833
Marshall Hall described the mechanism by which a
stimulus can produce a response independently of sensation or volition and
coined the term "reflex."
1833
Jan Evangelista Purkinje (Purkyne) discovered sweat
glands. He later discovered the neurons in the cortex of the cerebellum
and the conducting fibers in the heart which bear his name. He also
studied visual perception and devised the first system for classifying
fingerprints.
1833
Jean-Baptiste-Joseph-Dieudonn?Boussingault recommended
the use of iodized salt to cure goiter.
1835
J?s Jacob Baron Berzelius demonstrated that the
hydrolysis of starch is catalyzed more efficiently by malt diastase than
by sulfuric acid and published the first general theory of chemical
catalysis.
1835
Agostino Bassi demonstrated that a disease of silkworms
was caused by a fungus. This discovery gave impetus to the germ theory of
disease.
1835
Felix Dujardin associated the "sarcode" (protoplasm) of
protozoa with life processes.
1835
Richard Owen discovered Trichinella.
1835-38
Peltier maintained spermatozoa to be differentiated
body cells.
1835-39
Hugo von Mohl carefully described some details of
mitosis in plants. He recorded the appearance of the cell plate between
daughter cells. He remarked, "Cell division is everywhere easily and
plainly seen...in terminal buds and root tips."
1836
Charles Giles Bridle Daubeny investigated the
efficiency of different parts of the spectrum in photosynthesis.
1836
Fran?is Magendie demonstrated the need for dietetic
nitrogen.
1836
Theodor Schwann reported the action of pepsin and
described its properties. Putrefaction and fermentation were attributed to
the action of micro-organisms.
1836
Christian Gottfried Ehrenberg discovered giant axons in
the Crustacea.
1836-37
Frantz Schultze's and Theodor Schwann's experiments
opposing spontaneous generation.
1837
J?s Jacob Baron Berzelius classified fermentation as a
catalyzed reaction. He later identified lactic acid as a product of muscle
activity.
1837
Ren?Joachim-Henri Dutrochet recognized that chlorophyll
was necessary for photosynthesis.
1837
F?ix Dujardin asserted that the spermatozoa are
produced in the seminiferous tubules of the testis.
1837-38
Charles Cagniard-Latour (Cagniard de la Tour)
Theodor Schwann and Friedrich-Traugott K?zing independently announced that
yeast was a living organism which was responsible for fermentation. This
began the lengthy debate over whether fermentation was a chemical or a
vital process.
1838
Matthias Jakob Schleiden published his Beitr?e zur
Phytogenese, an important contribution to understanding the genesis of
plant tissues. He observed nucleoli but misinterpreted their significance
in considering them as nuclei forming within nuclei. Theodor Schwann
applied the same erroneous theory of cell formation to animal tissues but
correctly emphasized that "cells are organisms and entire animals and
plants aggregates of these organisms arranged according to definite laws."
1838
Christian Gottfried Ehrenberg separated bacteria from
other micro-organisms.
1838
Gerardus Johannes Mulder carried out the first
systematic studies of proteins. Mulder coined the term "protein".
1839
Jean-Baptiste-Joseph-Dieudonn?Boussingault
quantitatively studied the balance between the elementary constitution of
the maintenance ration of a cow and that of the excretions and the milk.
1839
Justus von Liebig maintained that nonliving ferments
cause fermentation. This began a controversy over whether fermentation was
a vital or a chemical process.
1839
Peirre-Fran?is Verhulst developed the logistic model of
population growth.
1839-46
Jan Evangelista Purkinje (Purkyne) proposed the term
"protoplasm" for living matter and, together with Hugo von Mohl,
established the protoplasm concept.
1840
1840
Justus von Liebig proposed that fermentation is
chemical and not dependent on living microbes.
1840
Jean-Pierre Lallemand held that the spermatozoa are
produced in the seminiferous tubules.
1840
Martin Barry expressed the belief that the spermatozoon
enters the egg.
1840
Publication of Justus von Liebig's Thierchemie which
united the fields of chemistry and physiology.
1840
Johannes M?ler established a theory of specific nerve
energies.
1840
Justus von Liebig pointed out that organic compounds in
plants are synthesized from carbon dioxide of the atmosphere while
nitrogenous compounds are derived from precursors in the soil.
1841
Hugh Miller appraised the Devonian deposits of the Old
Red Sandstone formation in Scotland, one of the most important
vertebrate-bearing sediments ever discovered. Miller believed that the
fossil record confirmed the biblical account of creation. He published
Footprints of the Creator in 1847, and opposed evolution to his death in
1856.
1841
Albrecht von K?liker (Koelliker) traced the
histogenesis of the spermatozoa and proved that they are differentiated
tissue cells.
1842
Julius Robert Mayer enunciated the first law of
thermodynamics and its applicability to living organisms.
1842
William Bowman described the histologic structure of
the nephron.
1842
Johann Japetus Steenstrup described the alternation of
sexual and asexual generations in plants and animals.
1843
Oliver Wendell Holmes observed the contagiousness of
septicemia.
1843
Richard Owen elaborated the distinction of homology and
analogy.
1843
Justus von Liebig speculated that organic acids such as
oxalic, tartaric, or malic were intermediates in the production of
carbohydrates by plants.
1844
Charles Darwin made his first sketch of the theory of
natural selection.
1844
Karl Ludwig showed that the Malpighian corpuscle of the
kidney acts as a passive filter and that the waste products in the
filtrate are concentrated as it passes through the tubules.
1844
John Dolland devised immersion microscopy.
1844
John William Draper showed that plants grown in
solutions of sodium bicarbonate can liberate oxygen in the light.
1845
Herrmann von Helmholtz and Julius Robert Mayer
formulated the laws of thermodynamics.
1845
Adolf Wilhelm Hermann Kolbe synthesized acetic acid,
previously obtainable only as the result of vital activity. He later
developed a method for the synthesis of salicylic acid.
1845
Carl Theodor Ernst von Siebold characterized Protozoa
as "animals whose organization is reducible to one cell." Later, he
discovered parthenogenesis in the honeybee.
1845
Miles Joseph Berkeley demonstrated that a mold was
responsible for potato blight. He also made important contributions to the
classification of fungi.
1845
Albrecht von K?liker demonstrated that spermatozoa are
cellular products of the organism. He also extended this finding to the
ovum, from which the organism is derived by cell division.
1846
Pierre-Joseph van Benedin concluded that a cysticercus
is an incomplete taenioid.
1847-49
Arnold Adolphe Berthold demonstrated by removal and
transplantation that the testis produces a blood-borne substance
conditioning sexual characteristics.
1847-49
Ignaz Semmelweis investigated the cause of puerperal
fever.
1848
Wilhelm Hofmeister made sketches of microspore mother
cells from Tradescantia which clearly show chromosomes in various stages
of meiosis, but he failed to grasp their significance.
1848
Carl Theodor Ernst von Siebold established Protozoa as
the basic phylum of the animal kingdom.
1849
Henri Victor Regnault and Jules Reiset published
extensive comparative studies of respiration and calorimetry.
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