Vierordt
Vierordt, Karl
ACHIEVEMENT(S): Blood measurement
NICKNAME/ALIAS: None
DATE/PLACE OF BIRTH: 1 July 1818, at Lahr, Baden [Germany]
DATE/PLACE/AGE AT DEATH: 22 November 1884, in Tubingen, Germany. Aged 66
DISCIPLINE: Medicine
FIELD: Physiology
LANGUAGE: German
PARENTS: Karl Friedrich Vierordt and ?
SIBLINGS: ?
SPOUSE: ?
CHILDREN: Hermann
EDUCATION: Universities of Heidelberg, Gottingen, Berlin and Vienna, 1836-41
MAJOR WORK: 'The Arterial Pulse in Healthy and Diseased States' 1855
LIFE AND TIMES: During his undergraduate years Vierordt studied with some of the greatest teachers of medicine of the age, including Naegli* (obstetrics), Wohler* (chemistry) at Gottingen; Schonlein* and Muller* (physiology) in Berlin; at Rokitansky* (pathology) at Vienna.
After graduating, Vierordt settled in Karlsruhe as a general practitioner and began his own physiological investigations. In 1842 he published his first paper, on the pathology and treatment of strabismus, a visual disorder. The following year he was appointed surgeon to the Grand Duke's regiment, and published the first of a series of papers on respiration.
In these papers (1843-45), based on experiments carried out in his home with no laboratory and the simplest of apparatus, Vierordt demonstrated that the percentage of carbon dioxide expired was less during rapid respiration than during slow respiration, but
that - because of the greater amount of expired air - more carbon dioxide was excreted for a given length of time during rapid respiration.
He noted that each breath, regardless of its duration, had a constant content of 2.5 per cent of carbon dioxide, and concluded that "the number of the respirations is the most effective regulator of the carbon dioxide excretion, and increases in general in a direct relationship to the increase in carbon dioxide excretion".
By these experiments, Vierordt demonstrated the role of carbon dioxide in controlling respiratory rate, a fundamental piece of physiological knowledge which made his name in Germany.
In 1849 he was appointed associate professor of theoretical medicine at the University of Tubingen, gave up his medical practice and devoted himself to a life of teaching and scientific research, lecturing at Tubingen on general pathology, therapy, materia medica, and the history of medicine.
In 1852 he published his first contribution to haematology, developing the work of the French pathologist Andral*, and describing an exact method of counting red blood cells using graduated capillary tubes.
Vierordt's method involved drawing the blood up a capillary tube, measuring the amount, and then blowing out the blood from the tube on to a glass plate covered with a thin film of egg albumen; after drying, a micrometer marked in squares was placed over the glass plate and the red blood cells counted under the microscope. Vierordt made the first count of red cells in his own blood, and estimated that his red blood cells numbered 5,174,000 per cubic millimetre, a remarkably accurate estimate.
In 1853 Vierordt was made professor of physiology. In October 1853 he first showed his sphygmograph, the first instrument to produce a graphic representation of the human pulse, and two years later he published the first treatise in which a normal and pathological pulse were comparatively studied. Soon afterwards (1855), Vierordt adapted the sphygmograph (by adding weights to its pans) to produce an instrument that could measure blood pressure more accurately than Ludwig's* kymograph of 1847.
Later, in 1858, he invented the haemotachometer to measure the rate of flow of blood with a pendulum which swung free in the current of blood. He was a pioneer in the field that was to be expanded and refined by the work of the physiologists Marey* and James Mackenzie.
In 1860 Vierordt published his best-known work, 'Rudiments of Human Physiology', which went to five editions. In 1864 he was appointed Rector of the University, and in 1868 Director of a new Institute of Physiology at Tubingen, the first in Germany devoted entirely to physiological research and teaching.
In the same year, inspired by the work of his good friend Fechner* on relations between the mind and the body, Vierordt began describing his investigations in a new field of physiology - which would become experimental psychology - in which he researched the sense of time, errors in time and speed perception, and the speed of voluntary movement. These investigations then led Vierordt's to make a series of studies on skin sensitivity and the sensations produced by movements.
In the early 1870s Vierordt returned to the study of haematology, using a spectrophotometer in order to make analyses of hemoglobin solutions, bile, and urine. In 1873-76 he applied the spectrometry discoveries of Frauenhofer*, Bunsen* and Kirchhoff*. Investigating the spectral absorption curves of pigments of blood, bile and urine, Vierordt made quantitative measurements of the spectral curves of haemoglobin using a spectrophotometer, and showed that a more accurate estimate of the haemoglobin content of the blood was obtained by taking readings at two different places on the absorption curve.
From 1876 Vierordt began to concentrate on the physiology of sound. During his last years he published several articles on the measurement of the intensity of sound and the conduction of sound by various bodies (1878-1884), but in May 1884 he was suddenly taken ill, and died a few months later.
ASSESSMENT: Best remembered for making the first accurate estimation of the number of red blood cells (1852) and his invention of the sphygmograph (1853), which introduced graphic methods for the study of the pulse.
EXTRA CONNECTIONS: None
ONELINER: Karl Vierordt, who started blood cell count
BIBLIOGRAPHY:
EB
Major, Ralph H., "Karl Vierordt" in Annals of Medical History, (November, 1938), X, no. 6, 463-473