Medicine in the 17th century reflected its deep roots in ancient history. Physicians continued to subscribe to humor and ventricular theories. But this began to change with new discoveries being made in anatomy and neurology. Leonardo da Vinci (1452-1519), for instance, sectioned animal and human corpses and produced exact anatomical sketches of what he found. And Andreas Vesalius (1514-1564) published his anatomical findings along with beautifully wrought drawings in his book On the fabric of the human body (1543). Vesalius’s book offered new anatomical and neurological information about the body, challenging the views embedded in Hippocratic and Galenic medical traditions. For example, Vesalius found that the network of arteries (rete Mirable) that Galen said produced animal spirits only existed in lower animals and not in humans.

While da Vinci’s and Vesalius’s findings advanced medical science in many respects, both researchers still held to ventricular theory of cognitive processing, given them by the ancients. DaVinci (1452–1519) attempted to determine an accurate description and location of the ventricles. He did this by injecting wax into the ventricular cavities of cattle and creating drawings of the imprint. In these drawings, Leonardo’s only deviation from the 400 AD version of ventricular theory of Nemesius was to localize perception and sensation in the middle ventricle rather than the lateral ventricles. DaVinci based his change on his finding that most sensory nerves converged on the midbrain. Finally, it was Thomas Willis, an English physician and a founder of neuroscience, who was to lead the way away from ventricular theory to the localization theories of later theorists.

Rene Descartes (1596-1650) also placed the ventricles at the center of his sensory processing theory. The nerves of the body and the filaments they contained were portrayed by Descartes as tubes that carried the animal spirits from the sense organs to the ventricles of the brain. Stimulation of a sense organ activated the filaments, which carried the animal spirits to the ventricles for further processing including a motor/muscular response to sensory stimuli.

Also operating in Descartes’ mechanistic renderings was a rational soul that worked independently of the sensory processing muscle action. The interaction between the soul and body took place, according to Descartes, in the pineal gland, and it was there that the person (but not other animals) were able to have a conscious appreciation of the sensation and it was there that voluntary movements of the muscles were initiated.

The 17th century provided a context for the expansion of medicine to include surgery and physiology. A significant 16th century contributor to the origins of surgery in medicine was Ambroise Pare. In 1552 Pare began tying off blood vessels of his patients with gunshot wounds to control bleeding from spurting arteries. This was a departure from the earlier practice of cauterizing the arteries with hot oil. Surgery prior to Pare was typically done by barbers. It was not considered respectable enough to be part of medical practice. Pare’s discoveries served to change that.

These dramatic humanistic and scientific changes, along with many others, had a profound impact on medicine in general and a specific impact on how people with speech and language disorders were diagnosed and medically treated. For example, William Harvey’s discovery of the organizational pattern in blood circulation led to the re-conceptualization of cerebral strokes (then called apoplexy) as a cardiovascular blockage rather than as a problem with the flow of animal spirits caused by excess phlegm in the ventricle of the brain.

Physicians of the period, subscribing to empiricist, experimental view of the day, began carrying out detailed case studies of people with communication disorders—specifically about different kinds of aphasia. In 1673, a Prussian physician Johannes Schmidt (1624-1690) reported on his patient, Nicolaus Cambier, who had a stroke resulting in what would later be called motor aphasia and dyslexia (Benton & Joynt, 1960; Golkenrath, 1984). This patient could successfully write to dictation, but could not read back what he had written.

At around the same time, a Swiss physician Jakob Wepfer (1620-1659) hypothesized that effects of a stroke were caused by bleeding in the brain. He also argued that these symptoms could be caused by a blockage of one of the main arteries that supply blood to the brain. From postmortem studies, he provided information on the carotid and vertebral arteries that supply blood to the brain. In 1658 Wepfer published a treatise on strokes, titled Historiae apoplecticorum. In another text, Observationes Medico-practicae de Affectibus Capitis Internis & Externis, eventually published in 1727 Wepfer described 13 cases of head injured patients with language disorders. He attributed their language problems to a loss of memory (Luzzatti & Whitaker, 1995/1996).

A third depiction of a form of aphasia during this period was that of Peter Rommel, a German physician. In 1683 Rommel published a detailed description of a motor aphasia calling it "a rare aphonia". The patient's understanding was intact, but conversationally she was poor and unable to repeat even short phrases to command. According to Rommel’s report, she retained the ability to recite long and well-learned Biblical passages.

Last, but by all means not least, were the important contributions of Hieronymus Mercurialis (1530-1606), a 16th century anatomist and physician. Mercuralis devoted a full chapter in his book on Treatises on the diseases of children (1583) to speech disorders.

Mercurialis divided speech disorders into three general types, based on their degree of severity. His determination of etiology and treatment were sometimes derived from the humor and ventricular theories of Hippocrates and Galen. For example, he based his speech remedies on whether he felt the brain or tongue to be dry or moist, hot, or cold.

If this defect has been caused by a fault of the brain, or the tongue, or the muscles, the defect arises either from dryness, or from excessive moisture and cold. If from dryness, as happens in fevers and after frenzies, care must be taken that both the tongue and the beginning of the spinal marrow be moistened by every means. To moisten the tongue a gargling of women’s milk is useful; it is also often useful to dampen the tongue with water of mallows, to which oil of sweet almonds should be admixed, and if leaves of water-lily are boiled together in water the greatest aid will be afforded…(Wollock 1977, p. 136).

Mercurialis also focused on specific articulatory organs when determining the cause and treatment of certain speech problems. He recommended treating problems differently, depending on the medical (physical) cause:

…if a polyp of the nose is causing it, all attention ought to be directed toward treatment of the latter. If it should occur from mutilation of the lips, no hope remains. If from a tooth having been knocked out, there is this one way only: an ivory tooth should be prepared and put in place of the missing one, secured to the remaining teeth; after the tooth grows back, the ivory one is removed. This remedy is of great service to both children and men (Wollock 1977, p. 136).

Finally, maintaining of the overall health of the body was a key element in Mercurialis’s therapeutic regimen.

The body must be exercised as much as possible; certainly the voice must be exercised in particular; and if there is anything which may benefit balbi and stutterers, it is a continuous loud and clear speaking.