iatromathematical,
iatromechanical, or physiatric) was founded on theories of physiology,
probably by Borelli, of Naples (1608-1679), although Sanctorius;
Sanctorius, a professor at Padua, was a precursor, if not directly
interested in establishing it. Sanctorius discovered the fact that an
"insensible perspiration" is being given off by the body continually,
and was amazed to find that loss of weight in this way far exceeded the
loss of weight by all other excretions of the body combined. He made
this discovery by means of a peculiar weighing-machine to which a chair
was attached, and in which he spent most of his time. Very naturally
he overestimated the importance of this discovery, but it was,
nevertheless, of great value in pointing out the hygienic importance
of the care of the skin. He also introduced a thermometer which he
advocated as valuable in cases of fever, but the instrument was probably
not his own invention, but borrowed from his friend Galileo.

Harvey's discovery of the circulation of the blood laid the foundation
of the Iatrophysical school by showing that this vital process was
comparable to a hydraulic system. In his On the Motive of Animals,
Borelli first attempted to account for the phenomena of life and
diseases on these principles. The iatromechanics held that the great
cause of disease is due to different states of elasticity of the solids
of the body interfering with the movements of the fluids, which
are themselves subject to changes in density, one or both of these
conditions continuing to cause stagnation or congestion. The school thus
founded by Borelli was the outcome of the unbounded enthusiasm, with its
accompanying exaggeration of certain phenomena with the corresponding
belittling of others that naturally follows such a revolutionary
discovery as that of Harvey. Having such a founder as the brilliant
Italian Borelli, it was given a sufficient impetus by his writings
to carry it some distance before it finally collapsed. Some of the
exaggerated mathematical calculations of Borelli himself are worth
noting. Each heart-beat, as he calculated it, overcomes a resistance
equal to one hundred and eighty thousand pounds;--the modern
physiologist estimates its force at from five to nine ounces!

THOMAS SYDENHAM

But while the Continent was struggling with these illusive "systems,"
and dabbling in mystic theories that were to scarcely outlive the men
who conceived them, there appeared in