||An epoch in physiology
was made in the eighteenth century by the genius and efforts of Albrecht
von Haller (1708-1777), of Berne, who is perhaps
as worthy of the title "The Great" as any philosopher who has been so christened
by his contemporaries since the time of Hippocrates. Celebrated as a physician,
he was proficient in various fields, being equally famed in his own time
as poet, botanist, and statesman, and dividing his attention between art
As a child Haller was so sickly that he
was unable to amuse himself with the sports and games common to boys of
his age, and so passed most of his time poring over books. When ten years
of age he began writing poems in Latin and German, and at fifteen entered
the University of Tubingen. At seventeen he wrote learned articles in opposition
to certain accepted doctrines, and at nineteen he received his degree of
doctor. Soon after this he visited England, where his zeal in dissecting
brought him under suspicion of grave-robbery, which suspicion made it expedient
for him to return to the Continent. After studying botany in Basel for
some time he made an extended botanical journey through Switzerland, finally
settling in his native city, Berne, as a practising physician. During this
time he did not neglect either poetry or botany, publishing anonymously
a collection of poems.
In 1736 he was called to Gottingen as professor
of anatomy, surgery, chemistry, and botany. During his labors in the university
he never neglected his literary work, sometimes living and sleeping for
days and nights together in his library, eating his meals while delving
in his books, and sleeping only when actually compelled to do so by fatigue.
During all this time he was in correspondence with savants from all over
the world, and it is said of him that he never left a letter of any kind
Haller's greatest contribution to medical
science was his famous doctrine of irritability, which has given him the
name of "father of modern nervous physiology," just as Harvey is called
"the father of the modern physiology of the blood." It has been said of
this famous doctrine of irritability that "it moved all the minds of the
century - and not in the departments of medicine alone - in a way of which
we of the present day have no satisfactory conception, unless we compare
it with our modern Darwinism."
The principle of general irritability had
been laid down by Francis Glisson (1597-1677) from deductive studies, but
Haller proved by experiments along the line of inductive methods that this
irritability was not common to all "fibre as well as to the fluids of the
body," but something entirely special, and peculiar only to muscular substance.
He distinguished between irritability of muscles and sensibility of nerves.
In 1747 he gave as the three forces that produce muscular movements: elasticity,
or "dead nervous force"; irritability, or "innate nervous force"; and nervous
force in itself. And in 1752 he described one hundred and ninety experiments
for determining what parts of the body possess "irritability" - that is,
the property of contracting when stimulated. His conclusion that this irritability
exists in muscular substance alone and is quite independent of the nerves
proceeding to it aroused a controversy that was never definitely settled
until late in the nineteenth century, when Haller's theory was found to
be entirely correct.
It was in pursuit of experiments to establish
his theory of irritability that Haller made his chief discoveries in embryology
and development. He proved that in the process of incubation of the egg
the first trace of the heart of the chick shows itself in the thirty-eighth
hour, and that the first trace of red blood showed in the forty-first hour.
By his investigations upon the lower animals he attempted to confirm the
theory that since the creation of genus every individual is derived from
a preceding individual - the existing theory of preformation, in which
he believed, and which taught that "every individual is fully and completely
preformed in the germ, simply growing from microscopic to visible proportions,
without developing any new parts."
In physiology, besides his studies of
the nervous system, Haller studied the mechanism of respiration, refuting
the teachings of Hamberger (1697-1755), who maintained that the lungs contract
independently. Haller, however, in common with his contemporaries, failed
utterly to understand the true function of the lungs. The great physiologist's
influence upon practical medicine, while most profound, was largely indirect.
He was a theoretical rather than a practical physician, yet he is credited
with being the first physician to use the watch in counting the pulse.