Gaspard Bauhin, or Caspar Bauhin (17 January 1560 - 5 December 1624), was a Swiss botanist who wrote 'Pinax theatri botanici' (1596), which described thousands of plants and classified them in a manner that draws comparisons to the later binomial nomenclature of Linnaeus. He was a disciple of the famous Italian physician Girolamo Mercuriale and he also worked on human anatomical nomenclature.

From childhood he was taught anatomy by his father and botany by his brother Jean almost twenty year his senior who became a botanist of some repute. In 1572 Gaspard entered the University of Basel, where Felix Platter (1536-1614) and Theodor Zwinger the Elder (1533-1588) were among his teachers, studying botany besides anatomy/medicine. He received the degree of Bachelor of Philosophy in 1575, and conducted his first medical disputation in 1577.

In October 1577 Bauhin went to Padua, where for eighteen months he studied anatomy with the Italian anatomist Girolamo Fabricius (Hieronymus Fabricius ab Aquapendente, 1537-1619). He saw seven bodies dissected "and even assisted myself in the private dissections." He also attended the teaching of Marco degli Oddi (1526-1591) and Emilio Campolongo (1550-1604) at the Hospital St. Francis, and probably that of Melchior Wieland (Melchiore Guillandini, 1519 or 1520-1589) in the botanical garden. In 1582 he was appointed to the Greek professorship in that university, and in 1588 to the chair of anatomy and botany. He was later made city physician, professor of the practice of medicine, rector of the university, and dean of his faculty.

He then travelled all over Italy, visited Bologna and received instruction in anatomy from Giulio Cesare Aranzi (1530-1589), before going to Montpellier, where he signed the register in the spring of 1579. But by his own account he spent more time in Paris attending the anatomy sessions conducted by Sévérin Pineau (ca. 1550-1619), professor of anatomy and surgery, "whom I assisted in dissecting at his request." In May 1580 he was in Tübingen.

Although Bauhin made no major original contributions in anatomy, he made an important contribution by introducing a much improved nomenclature of anatomy. His principles are partly still in use. Especially by the designation of muscles he introduced new, more logical designations.

He himself believed that he was the first to describe the ileocecal valve, which was long known as the valvula Bauhini; and in a number of his anatomical writings he gives an account of how he first found it during a private dissection that he performed as a student in Paris in 1579. There is no doubt that Bauhin's contribution as a teacher of anatomy was considerable.

His book Theatrum anatomicum became a very popular text because it was systematic, provided adequate coverage of the ancient authorities did not dwell too much on the controversies, had useful footnotes, mentioned anatomical anomalies, and gave pathological findings. He is credited with giving the name of areole to the pigmented area around the nipple. Bauhin was also active in the field of dentistry, but let himself be strongly influenced by the writings of Galen and Aristotle.

In the field of botany he left a large number of writings. He became famous as a pioneer in botanical classification and in 1623 published his work Pinax theatri botanica, the most recognised of the earlier works trying to name and catalogue all known plants. Altogether he described 6,000 species. He is also remembered for separating botany from material medica. In Pinax he discarded the old alphabetical manner of enumeration and stated that any sound method of classification must be based on affinities. Consequently, he distinguished between genus and species and introduced a system of binominal nomenclature. His botanical work was commemorated by Charles Plumier (1646-1704), who gave the name Bauhinia to a family of tropical trees; and Linnaeus (Carl von Linné, 1707-1778), in memory of both Gaspard and his brother Jean, called one species of this family Bauhinia bijuga.

After the death of Felix Platter in 1614 Bauhin succeeded his teacher as archiator (chief medical officer) to the city of Basel, and the following year was appointed professor of practical medicine

He was married three times: In 1581 to Barbara Vogelmann of Montbéliard, by whom he had one daughter; in 1596 to Maria Bruggler of Bern; and sometimes after 1597 to Magdalena Burckhardt, by whom he had two daughters and one son, Jean Gaspard (1606-1685), who succeeded his father as professor of anatomy and botany in 1629 and became professor of the practice of medicine in 1660. In 1658 Jean Gaspard published the first volume, all that was ever published of the intended twelve, of his father's Theatrum botanicum.

The Pinax theatri botanici (English, Illustrated exposition of plants) is a landmark of botanical history, describing some 6,000 species and classifying them. The classification system was not particularly innovative, using traditional groups such as "trees", "shrubs", and "herbs", and using other characteristics such utilization, for instance grouping spices into the Aromata. He did correctly group grasses, legumes, and several others. His most important contribution is in the description of genera and species. He introduced many names of genera that were later adopted by Linnaeus, and remain in use. For species he carefully pruned the descriptions down to as few words as possible; in many cases a single word sufficed as description, thus giving the appearance of a two-part name. However, the single-word description was still a description intended to be diagnostic, not an arbitrarily-chosen name (in the Linnaean system, many species names honor individuals, for instance).

In addition to Pinax Theatri Botanici, Gaspard planned another work, a Theatrum Botanicum, meant to be comprised in twelve parts folio, of which he finished three; only one, however, was published (1658). He also gave a copious catalogue of the plants growing in the environs of Basel, and edited the works of Pietro Andrea Mattioli (1500-1577) with considerable additions. His principal work on anatomy was Theatrum Anatomicum infinitis locis auctum (1592).

In addition to the species of tropical tree named after him, there is also:

Bauhin's gland: A small, deeply placed mucous gland near the apex of the tongue.

Bauhin's valve: A valve consisting of two mucous folds located between the border of terminal ileum and ascending colon.

Bauhin was a truly original scientist whose influence in both anatomy and botany lasted for well over a century. His great merit was his ability to treat his subject in an orderly and methodical manner, for he had a capacity to think clearly and an ability to work without tiring. Quiet and reserved, he can be remembered in William Harvey's (1578-1657)) words concerning him: "a rare industrious man."