Filippo Pacini

Filippo Pacini was the son of Francesca Pacini, a cobbler, and Umiltà Dolfi. From early on his parents wanted him to become a bishop and be committed to religious studies. He was educated, with public assistance, at the Pistoia Episcopal seminary and later at the classical academy. Already while a boy he showed a great love for the natural sciences, and in 1830 he abandoned his ecclesiastical career and turned to medicine.

He attended the surgical school – Scuola Medica Pistoia – founded 1666 in his native city, and in 1830 entered the medical school attached to the Ospedale del Ceppo. In 1835, while still a student, he presented his discovery of the particles that now bear his name to the Florentine Società medico-fisica. This, however, was not much appreciated by the learned men of his time. He was not deterred, however, continuing his investigations with an Amici-microscope lent him by Niccolò Puccini. Pacini graduated in surgery in 1839 and presented the results to the scientific congress in Pisa that year. He graduated medicine in 1840.

In the latter year, as a consequence of the reform of the medical studies in Toscana, Pacini went to Pisa where he was appointed assistant to professor Paolo Savi (1798-1871), now known for Savi's warbler, in the Institute of Comparative Anatomy. He assumed a similar post at the Institute of Human Anatomy in 1843, and became a substitute teacher there the following year.

With a new microscope, perfected by Pacini and built with the assistance of Giovanni Battista Amici (1786-1863), he investigated the human retina and published his results in 1844. Still, he found no recognition, even meeting animosity. In 1847, Pacini therefore began to teach descriptive anatomy at the Lyceum in Florence, where he also taught painters. He subsequently, in 1849, became director of the anatomical museum and professor of general and topographical anatomy at the medical school there (Istituto di Studi Superiori, and from 1859 also teacher of microscopical anatomy. In 1852 he published his works on the electric organ of the Gymnotus electricus compared to the equivalent organ in other electric fishes.

Throughout Pacini's career at the Florence medical school, the professor of descriptive anatomy was Luigi Paganucci (1808-1886). As a teacher Pacini, convinced of the fundamental importance of the biological sciences to medical education, initiated a number of new programs; he was, however, occasionally frustrated and embittered by the antagonism of Maurizio Buffalini (1785-1875), director of the department of internal medicine.

Pacinian corpuscles
Pacini saw the corpuscles that are now named for him early in his career; indeed, he discovered them in a hand that he was dissecting as a student in the anatomy class in Pistoia hospital in 1831, when he was nineteen. He first saw the corpuscles around the digital branches of the median nerve, and suggested that they were "nervous ganglia of touch"; but he soon found them also in the abdominal cavity. Although he studied these corpuscles microscopically from 1833 on, Pacini published his research only in 1840, when his Nuovi organi scoperti nel corpo umano appeared. However, he had mentioned them at a scientific meeting in Florence in 1835.

The name "Pacini's corpuscles" was proposed in 1844 by Henle, and by Kölliker, who had confirmed their existence. In 1862, however, the Viennese anatomist Carl Langer claimed priority for Abraham Vater - although Vater's work, published in 1741, had been forgotten and was certainly unknown to Pacini. Vater noted the corpuscles in the skin of the fingers. He called them the papillae nervae and they were later depicted by Lehmann in 1741. They were apparently forgotten until they were rediscovered in 1831 by Pacini. At all events, Pacini was the first to describe the distribution of the corpuscles in the body, their microscopic structure, and their nerve connections; he also interpreted the function of the corpuscles as being concerned with the sensation of touch and deep pressure. In 1844 Friedrich Gustav Jacob Henle (1809-1885) and Albert Kölliker (1817-1905) named these structures Pacinian corpuscles.

No love in the time of the cholera
During the cholera epidemics in Florence 1854-1855, Pacini microscopically examined the blood and faeces of those afflicted with the disease as well as the changes of the intestinal mucosa of cholera corpses. This work was done with the support of his assistant, the later professor og ophthalmology in Bologna, Francesco Magni (1828-1888). These investigations proved the presence of millions of rod-shaped corpuscles which he considered to be microbes, and so named them.

These rods had been brought to Europe from India and, not finding a habitat for lasting existence, subsided after 2-3 years.

Pacini published his findings in a report, Osservazioni microscopiche e deduzioni patalogiche sul cholera asiatico, in which he stated that cholera is a contagious disease, characterized by destruction of the intestinal epithelium, followed by extreme loss of water from the blood (for which condition he later recommended, in 1879, the therapeutic intravenous injection of saline solution). Pacini went on to declare that the intestinal injuries common to the disease were caused by living microorganisms - which he called "vibrions"; he further provided drawings of the vibrions that he had observed microscopically in abundance in the intestine of cholera victims.

Despite the significance of his researches, Pacini was overlooked when, following the epidemic of 1866, the Italian government distributed medals for meritorious work against cholera. In 1884 Koch rediscovered the cholera vibrio, and named it "Comma Bacillus"; by applying his rigorous postulates, he was further able to that the bacillus was the sole cause of the disease. Koch presented his findings at the Cholera Commission of the Imperial Health Office in Berlin; the commission also recognized Pacini's priority in discovering the microorganism.

His microscopes
Pacini was primarily interested in microscopical research, advocating the teaching of microscopic anatomy. As early as 1833 he had access to a primitive instrument, and in 1843 was given a good one by the Pistonian philanthropist Niccolò Puccini. This was used for a course in practical microscopy that year. The following year Pacini designed his own microscope, which he built the next year with the help of Giovanni Battista Amici; this was the best to which he had ever access. Amici was the inventor of the achromatic lens. In 1847 he published a plea for the teaching og histology, and in 1861 he presented a collection of selected microscopical preparations to the first Italian Exposition, held at Florence.

In 1868 Pacini constructed another compound – which he called "inverted" – instrument for photographic and chemical use. This, together with the 1845 microscope, is preserved in the Museo di Storia della Scienza in Florence.

He published further notes on histological technique as late as 1880. His specific contributions include a description of the membrana limitans interna of the human retina (1845) and reports on the electric organ of the Nile Silurus (1846 and 1852) and on the structure of bone (1851). He also published work in practical anatomy, including a study of the muscular mechanics of respiration in man (1847). He later - in 1870 - developed a method for artificial respiration based upon a rhythmic movement of the shoulders of the unconscious subject, to be used for "reliving" of drowned persons and persons poisoned with narcotics

The man
Pacini was a pious and charitable man. He never married, and his work was generally unrecognised. He died in a poorhouse, having spent all his money on scientific investigations and medical care for his sisters, and was buried in the cemetery of the Misericordia in Florence. In 1935 his remains were transferred with the remains of two other anatomists, Atto Tigri (1813-18759 and Filippo Civinini (1805-1844), to the church of Santa Maria delle Grazie in Pistoia.

Despite his international recognition, Pacini experienced the disappointment of not being elected a member of the Accademia dei Lincei in Rome. Maybe due to his nervous character and frequent unpleasant behaviour.

A complete list of his works contains fifty-five items.

In 1965 the international committee on nomenclature adopted Vibrio cholerae Pacini 1854 as the correct name of the cholera-causing organism.

• Sopra un particulare genere di piccoli corpi globulari scoperti nel corpo umano da Filippo Pacini.
  Archivio delle scienze medico-fisiche toscana, 1835, 8.
  Also in Nuovo giornale dei letterati, parte scientifica, 1836, 32: 109-114.
• Nuovi organi scoperti nel corpo umano. Pistoia, tipog. Cino, 1840.
• Nuove richerche microscopiche sulla tessitura intima della retina.
  Nuovi annali delle scienze naturali, July-August 1846.
  Reprinted separately in Bologna 1845.
• Sopra l'organo elettrico del Siluro del Nilo.
  Nuovi annali delle scienze naturali, July 1846.
• Sulla questione della meccanica dei muscoli intercostali.
  Gazzetta toscana delle scienze medico-fisiche, 1847, 5: 153-156.
• Cosa è ed a che è buona l'anatomia microscopica del corpo umano.
  Gazzetta toscana delle scienze medico-fisiche, 1847, 5: 193-199.
• Nuovo richerche microscopiche sulla tessitura intima delle ossa.
  Gazzetta medica italiana federativa, November 1851.
• Osservazioni microscopiche e deduzioni patalogiche sul cholera asiatico.
  Gazzetta medica italiana federativa toscana, Firenze, volume 4, December 1854.
  Reprinted in Lo Sperimentale, Firenze, 1924, 78: 277-282.
• Della natura del colera asiatico.
  Cronaca medica di Firenze, Augusst 10 and November 10, 1866.
• Il mio metodo di respirazione artificiale per la cura dell'asfissia.
  L'Imparziale, Firenze, 1870; 10: 481-486.