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HERMANN LUDWIG FERDINAND VON HELMHOLTZ as a youth did not want to be a physician;
he wanted rather to be a physicist, or a mathematician. Later in life he became
a scientific investigator who made outstanding contributions in each of these fields.
Of him, Sigerist Wrote: “It was a rare stroke of luck for medical science
that a man with such eminent physical and mathematical gifts should be forced by
circumstances to devote a considerable part of his life to medical science.”
Medical men may remember Helmholtz best for his inventions; the ophthalmoscope and
the ophthalmometer. However, his original research, both in physical optics and
in color sensation, was much more extensive, and of almost equal importance to medicine
were his studies of acoustics and of the mechanism of the middle ear. The scope
of Helmholtz’ interests and of his original work is amazing; in addition to
the sciences of medicine, optics, land acoustics, the great German scientist made
important contributions to knowledge in psychology, chemistry, physiology, physics,
mechanics, hydrodynamics, electricity, color, meteorology, and mathematics. Hall
comments that “It is doubtful if the world has ever produced a man who combined
grater breadth of knowledge and greater depth of wisdom, with keenness of vision,
persistency and patience of pursuit, and modesty of claim.”
Herman Helmholtz was born August 31, 1821, at Potsdam, near Berlin. He was the son
of Ferdinand Helmholtz, teacher in the Gymnasium (high school) and a man of high
culture and intelligence. The mother was a daughter of a Hanoverian artillery officer
named Penne – a lineal descendant of William Penn, the great Quaker who came
to North America and founded Pennsylvania. A grandmother was of French origin. Helmholtz
thus had German, English, and French blood in his veins. One of four children in
a family of modest means, he was sickly as a child and had poor health throughout
a long life. Confined to his room by illness for long periods, the boy sought amusement
through activity of mind. He read widely and whiled away time with a set of blocks,
from which early he gained concepts of geometry. He grew to love nature and enjoyed
hikes in the country, gaining from them an appreciation for natural laws. His early
interest in physics was revealed in his construction while in high school of optical
apparatus, using odd lenses; in his surreptitious application of optical principles;
and in his drawing diagrams, while attending lectures, illustrating passage of light
through telescopes. He developed his mathematical talents without the aid of special
instruction.
Young Helmholtz wanted to devote his life to the study of physics but the limited
means of his father dictated otherwise. Surgeon-General Mursinna, a relative, advised
the boy to study medicine, and in 1838 arranged for his admission to the Royal Medico-Chirurgical
Friedrich-Wilhelms-Institute in Berlin –an appointment given freely to youths
on condition that afterward they become surgeons in the Prussian army.
During his years in medical school, Helmholtz came under the influence of Hohannes
Miiller, one of the Institute’s great teachers, a circumstance which led to
his association with DuBois Reymond, Briicke, Gustav Magnus, Kirchhoff, Virchow,
land others who later joined with him in founding the Berlin Physical Society.
During his student years, Helmholtz suffered an attack of typhoid fever and was
treated at no cost to him at Charite Hospital. With money saved from his stipend
during this period, he purchased a compound microscope, an instrument rarely possessed
by students in those days. In 1842, Helmholtz, at the age of 21, presented his doctoral
thesis, On the Structure of the Nervous System of the Invertebrates, in which he
contributed basic knowledge; proof that nerve fibers are branches of nerve cells,
a fact there before unknown.
For more than 50 years thereafter, from this time (1842) on to 1894, when Helmholtz
reached the age of 73, papers flowed from his pen in almost uninterrupted succession.
By
the end of his career, he had published 217 papers and books.
Serving for six years, after graduation in 1842, as a medical officer in the Prussian
army, Helmholtz continued research in his spare time. Among subjects he investigated
were fermentation (in which he preceded Pasteur), and production of heat in contracting
muscle. In 1847, at the age of 26, he published in pamphlet form what perhaps was
his greatest scientific accomplishment: postulation and proof of the law of conservation
of energy. Though now axiomatic, Helmholtz’ theses…that energy is indestructible
and that energy may be transformed but is never lost or destroyed…represented
the first clear and unmistakable presentation of an idea, applicable to medicine
as well as to mechanics, that had been only hinted at by earlier scientific workers.
In 1848, Helmholtz was allowed to leave the army so that he might become Professor
of Anatomy at the Academy of Art in Berlin. In 1849, he became Professor of Physiology
in Konigsberg. Continuing research there, Helmholtz measured the velocity of the
nerve impulse-believed by his teacher, Johannes Miiller, to be technically impossible.
At this time, too, he began intensive study of the physiology of the senses.
In the course of studies relating to physiologic optics, in 1850, Helmholtz invented
the ophthalmoscope. He once wrote how the discovery came about: “I was endeavoring
to explain to my pupils the emission of reflected light from the eye, a discovery
made by Brucke, who would have invented the ophthalmoscope had he only asked himself
how an optical image is formed by the light returning from the eye. In his research
it was not necessary to ask it, but had he asked it, he was just the man to answer
it is quickly as I did, and to invent the instrument. I turned the problem over
and over to ascertain the simplest way in which I could demonstrate the phenomenon
to my students. It was also a reminiscence of my days of medical study, that ophthalmologists
had great trouble in dealing with certain cases of eye disease, then known as black
cataract. The first model was constructed of pasteboard, lenses and cover glasses
used in the microscopic work. It was at first so difficult to use, that I doubt
if I would have persevered unless I had felt that it must succeed; but in eight
days I had the great joy of being the first who saw before him a living human retina.”
The ophthalmoscope consists essentially of a converging or concave mirror for concentrating
light through the patient’s pupil thus illuminating the retina and other parts
of the eye. The eye of the observer is behind a small hole in the centre of the
mirror. In front of this opening is a magnifying lens or combination of lenses.
Invention of this instrument opened a new era, not only for ophthalmologists, but
for other practitioners of medicine, as well. Ophthalmoscopic examination of the
retina, which may be regarded as an outlying portion of the brain, gives information
of value, not only in diagnosis of diseases of the eye, but also in assessing pathologic
states in other parts of the body.
Helmholtz’ interest in physiologic optics began with the ophthalmoscope and
did not end until he felt he had completely mastered the whole field. Next problem
of attract his attention embraced optical constants in the eye. In order to determine
the curvature of refractive surfaces, Helmholtz developed the opthalmometer, by
means of which refractive powers and visual defects of the individual eye might
be measured. This work be continued until he could lay down rules for guidance of
practicing ophthalmologists in use of the instrument in solution of problems of
ocular accommodation, and in measurement necessary for preparation of lenses for
correction of visual defects.
Helmholtz next turned to problems of color sensation, which he explored intensively,
including causes of color blindness. This work on optics, begun in Eonigsberg, was
continued in Bonn, and in Heidelberg, culminating in 1867 with publication of his
classic work, Handbook of Physiologic Optics.
In 1856, Helmholtz, then 36 years of age, accepted the Chair of Anatomy and Physiology
at the University of Bonn; three years later, in 1859, he became Professor of Physiology
at Heidelberg, where he remained until 1871.
Paralleling his work on optics, and of almost equal importance to medicine, was
Helmholtz’ work on physiologic acoustics. Begun in Konigsberg, the greater
part of these studies was carried out in Bonn. Before Helmholtz’ research,
knowledge of acoustics was rudimentary and largely empiric. He combined his advanced
knowledge of physics with experimental physiology and went on, and only to define
physical principles underlying transmission of sound, but followed its course through
the middle ear to the brain. He accurately described, in detail, the anatomy of
the middle ear, and the function of each tissue therein. Results of these studies
were outlined in his book, Sensations of Tone as the Physiological Basis of Music,
published in Heidelberg in 1863. These developments had been preceded by a number
of papers over the years, including: Vowel Tones: The physical Basis of Harmony
and Dissonance; The Theory of Organ Pipes; Musical Temperature; and Motions of the
Strings of a Violin. His monograph on anatomy of bones of the middle ear appeared
in 1869.
After 1867, Helmholtz’ work and publications were predominantly in the field
of physics and mathematics, although his contributions relating to cerebral functions
were of fundamental value to the field of psychology. In 1871, Helmholtz, logically,
was invited to return to Berlin to take over the Chair of physics at the University
of Berlin, to succeed the great Magnus. In this position he was accorded recognition
as the foremost physicist in Germany. During the next eleven years he contributed
a total of 60 scientific papers on various subjects.
In 1888, Helmholtz became the first director of the Imperial Institute for Physics
and Technology, at Charlottenburg, near Berlin. In addition to these new duties,
he maintained his Chair at the University until his death. In his later years, instead
of declining, Helmholtz seemed to increase in mental power. More and more, he devoted
himself to establishment of fundamental principles related to dynamics, hydrodynamics,
thermodynamics, electrodynamics, and other complex physical problems. He continued
his popular science lectures, begun in Konigsberg.
Despite his heavy program of scientific research, Helmholtz, was a lover of art
in all its forms; he was an accomplished musician; and, for recreation, he loved
a climb in the mountains or a walk in a meadow. Some of the answers to his most
puzzling problems, he related, came to him during his visits to nature. During his
lifetime he was twice married. Two children were born to each union. His home life
has been described as quiet, cultural, and pleasant.
Emperor Wilhelm I ennobled Helmholtz and often received him in the imperial domestic
circle. Helmholtz’ seventieth birthday anniversary was celebrated as a national
event, for which a gold medal was struck in his honor. The Kings of Sweden and of
Italy, the Grand Duke of Baden, and the President of the French Republic each conferred
special honor upon him.
Despite age, Helmholtz continued to be active; in 1892, he attended meetings of
the British Association for the Advancement of Science, in Edinburgh, Scotland;
and in 1893, the International Exposition in Chicago, after which he toured the
United States and Canada. On his homeward journey, he felt on shipboard and suffered
concussion of the brain. From this injury he only partially recovered, and in July,
1894, he suffered a stroke. Death took the great physicist and physician, September8,
1894, just eight days after his seventy-third birthday anniversary.
Helmholtz…teacher, experimenter, physician, and physicist…left the
world a great heritage of scientific advancement. There was an intimate relationship
between his functions as professor and as original investigator; he investigated
because he wanted to speak of matters with knowledge gained firsthand. Again and
again he took up problems that he might master them himself, so that he might make
clear explanations to his pupils. Students profited…and so did the entire
world…for the work of the kindly, reserved professor was spread round the
globe among practitioners of medicine and among those active in several other fields
in science.
THE PICTURE
Among great contributions to medicine in the nineteenth century was the ophthalmoscope,
instrument used for inspection of the interior of the eye, invented in 1850 by Hermann
Ludwig Ferdinand von Helmholtz (1821-1894), Professor of Physiology at Konigsberg.
Physician by training and teacher by profession, Helmholtz became Germany’s
foremost physicist, succeeding to the Chair of Physics at the University of Berlin.
His contributions to medicine’s knowledge of acoustics nearly equaled those
to physiologic optics. His discoveries in physics advanced knowledge in a dozen
scientific fields, earned him ennoblement, and brought him world-wide recognition
during his lifetime.
REFERENCES:
Ackerknecht, E.H.: Unpublished monograph.
Ackerknecht, E.H.: A Short History of Medicine. New York, Bonald Press Co., 1955.
Arrington, George E., Jr.: A History of Ophthalmology. New York, MD Publications,
1959.
Friedenwald, H: The History of the Invention and of the Development of the Ophthalmoscope.
The Journal of the American Medical Association, Vol.38, No.9, March 1, 1902.
Goodspeed, A.W.: Contributions of Helmholtz to Physical Science. The Journal of
the American Medical Association, Vol.38, No.9, March 1, 1902.
Hall, W.S.: The Contributions of Helmholtz to Physiology land Psychology. The Journal
of the American Medical Association, Vol.38, No.9, March 1, 1902.
Knapp, H: A Few Personal Recollections of Helmholtz. The Journal of the American
Medical Association, Vol.38, No.9, March 1, 1902.
Koenigsberger, L: Hermann von Helmholtz, 3 vols. Braunschweig, 1902.
McKendrick, J.G: Germann Ludwig Ferdinand von Helmholtz, London, T. Fisher Unwin,
1899.
Randall, B.A: The Debt of Otology to Helmholtz, The Journal of the American Medical
Association, Vol.38, No.9, March 1, 1902.
Sigerist, H.E.: The Great Doctors, New York, Norton & Co., 1933.
Wood, C.A.: Hermann von Helmholtz, The Inventor of the Ophthalmoscope. The Journal
of the American Medical Association, Vol.38, No.9, March 1, 1902.
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