A vivisection performed on a dog on 23 July 1622 revealed the existence of previously unidentified vessels that Gaspare Aselli termed the lacteals. This discovery, which identified the structures responsible for absorbing nutrients from the intestinal tract, challenged the long-standing Galenic assertion that chyle was transported directly through the veins.
Academic Training and Early Career
Born in Cremona in 1581 to a wealthy patrician family, Aselli pursued his foundational education at the University of Pavia. He earned degrees in medicine, surgery, and philosophy before establishing his medical practice in Milan. His clinical expertise gained significant institutional recognition, leading the Milanese Senate to designate him an honorary citizen. By 1612, he had attained the position of Head Surgeon for the Spanish Armada in Italy, a role that preceded his final academic appointment as a professor of anatomy and surgery at the University of Pavia.
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Aselli characterized the lacteals as a fourth category of vessel, distinct from nerves, arteries, and veins. Through his experiments, he noted that these vessels were only visible following digestion and recognized the presence of internal valves that prevented backflow. He identified a cluster of mesenteric glands associated with these channels, later referred to as Aselli's gland or the pancreas Aselli. While he incorrectly hypothesized that these vessels terminated in the liver, his work provided critical evidence against the traditional view that the liver served as the primary source of blood.
Posthumous Publication and Influence
The volume gained scientific distinction for its use of polychrome woodcut prints, created by either Cesare Bassano or Domenico Falcini, to differentiate between anatomical structures. These illustrations were the first of their kind to prioritize scientific accuracy through color. His insights into physiological processes were subsequently reprinted in cities across Europe, including Basel, Leiden, and Amsterdam, influencing contemporaries like Adriaan van den Spiegel and anticipating elements of William Harvey's research on blood circulation.
Fast facts
- Born: 1581, Cremona
- Died: 1626, Milan
- Education: University of Pavia
- Primary Field: Anatomy and Surgery
- Notable Discovery: Lacteal vessels
- Key Publication: De lactibus sive Lacteis venis (1627)
- Burial Site: San Pietro Celestino church
Questions readers ask
What was the significance of the illustrations in Aselli's work?
De lactibus sive Lacteis venis was the first scientific publication to employ polychrome woodcuts to distinguish between different types of vessels.
Did Aselli discover the true termination of the lacteal vessels?
No, he mistakenly believed they led to the liver; the true continuity with the thoracic duct was later established by Jean Pecquet.
Achievements
- Held posts at University of Pavia
