Vincenzo Malacarne (Fig. 1) was born in Saluzzo in the province of Cuneo, Piedmont region, Italy, on September 28, 1744. Educated by the Dominicans, he manifested a precocious talent and a particular predilection for literary studies, including the classic languages. In 1762, he entered in the Royal College of Turin’s Provinces, where young promising students from Piedmont were selected and supported by the State for studying surgery [1]. He obtained the graduation at the college in 1769. Between 1775 and 1783, Malacarne was called as director of the thermal baths and professor of surgery of Acqui Terme in the province of Alessandria. Isolated from the animated intellectual life of the capital, Malacarne focused on his researches on the brain and the cerebellum in particular. He eventually published two fundamental books in the history of neurology, where he made the first complete description of the human cerebellum, namely the Nuova esposizione del cervelletto umano (1776) [2] and the Encefalotomia nuova universale (1780) [3]. In 1783, he came back to Turin, called to the position of “main surgeon of the town.” In 1789, he was called to the chair of Surgery and Obstetrics at the University of Pavia, maintaining this role only 4 years. Finally, in 1794, Malacarne was called to the chair of Practical and Theoretical Surgery at the University of Padua, passing to the chair of Surgical Principles and Obstetrics in 1806. He remained in Padua until his death, on September 4, 1816.

Fig. 1
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Vincenzo Malacarne (1744–1816)

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Malacarne represented a perfect example of an eighteenth century “letterato,” term that can be translated with “scholar,” or “intellectual,” rather than with “man of letters” [1]. This particular figure, typical of the Enlightenment, combined interests in humanities, sciences, and politics, embodying the ideal of an encyclopedic and universal culture. Malacarne did not confine his scientific interest only to a specific branch of medical sciences, because he made important contributions in anatomy and surgery [4, 5], teratology [6,7,8], obstetrics [9], neurology [2, 3], and history of medicine [10]. In general, in almost all these studies, Malacarne adopted an interdisciplinary approach based on the correlation between anatomy, surgery, and clinics. For instance, he founded surgical anatomy by stressing the importance for surgeons of knowing clinical manifestations and anatomical seats of diseases, as giving the fundamental insights for guiding their hands [5]. In his scientific writings, he paid much attention to the language and the style of exposition, to the point that he sent many of his manuscripts to expert reviewers for corrections both in the form and in the scientific content [11]. Moreover, he used his knowledge of classic languages to coin scientific terms based on Greek etymologies. In particular, he introduced new definitions in teratology, which are still used today, such as acranius, microsomia, macrosomia, micromelia, macromelia, and polymelia [12].

Malacarne’s interest on the brain and nervous system dated back to the period when he was student of surgery in Turin. Training his surgical skill by dissection of animals, he was able to prove the existence of the pineal gland in birds against the opinion of many naturalists [13]. Since 1772, Malacarne studied many cases of “cretinous” found along the Po Valley, which inspired him the fundamental concept of the organic nature of mental diseases [14]. Note that “cretin” and “idiot” were terms in common usage at that time for describing different levels of intellectual disability. Their current pejorative sense emerged much later.

Between 1775 and 1782, he dissected the bodies of three “cretinous,” describing the brain anomalies which could give account of their mental disorders [15]. In particular, he noted that the cerebellum was underdeveloped with regard to the number of lobes and folia compared to normal brain, forming his first hypothesis on the relationship between intelligence and the cerebellum: the degree of human intelligence was proportional to the number of folia of the cerebellum. Based on his anatomical analysis, he advanced possible surgical interventions for correcting some of the anomalies and partially restoring brain and cerebellum physiology [15].

With regard to the cerebellum, his complete description published in 1776 became immediately a classic on the subject, praised by the Swiss anatomist and physiologist Albrecht von Haller (1708–1777) [16] and by the French anatomist Félix Vicq d’Azyr (1746–1794) [17]. Malacarne introduced terms such as tonsil, pyramid, lingual, and uvula that are still in use today [18]. He outlined a significant research program for understanding brain functions, based on anatomo-clinical method: given a big hospital, all mental characteristics of the patients should be noted and then correlated with the morphology of their brains through dissection after death [2]. In this scientific context of exchanges and polemics, he quantified the units of the cerebellar internal structures, the lamellae being numbered for a systematic description of the human cerebellum. He thought the mental faculties depended on their number: so, he considered a relation between the number of cerebellar lamellae and the expression of intellectual faculties. In this way, we can say that he made first statistics on human faculties.

Between 1778 and 1789, Malacarne had an epistolary exchange with the Swiss naturalist Charles Bonnet (1720–1793) about the seat of the soul and the intelligence in the brain [3, 19]. In patients affected by cretinism, as already stated, Malacarne observed that there was a reduction of the cerebellar size and a decrease in the number of folia. He reported a wide variation in the number of folia from 500 to 780 while in an idiot, the number was 340 [2]. He was able to predict the development of folia before the dissection of a patient, on the basis of the more or less intelligence manifested during his/her life [19]. Bonnet, who at the beginning of the correspondence was quite doubtful on the possibility to find the specific seat of human mind in the brain, praised this result a lot. They also discussed whether such variability was innate or acquired by experience. Malacarne proposed bringing up twins of different species of mammals and birds in poor and enriched environments and then verifying the number of folia [19]. It is not known whether the experiment was ever done. At any case, the most interesting aspect of his finding remains the hypothesis that the number of folia is influenced by the environment, thus providing the first nature-nurture hypothesis made on the basis of observations, and the concept of neuroplasticity in the scientific literature [20].

If Malacarne’s anatomical research on the cerebellum could be considered the starting point of the discovery of this organ, his proposals concerning cerebellar function were much less successful. That the degree of intelligence could be proportional to the cerebellum’s folia represented a hypothesis already advanced by Erasistratus a millennium and a half earlier in the case of the cerebral gyri [18, 21]. It is worth mentioning, however, that recently acquired evidence shows that the human cerebellum is activated during mental recall of emotional personal episodes and during learning of a conditioned or unconditioned association involving emotions [20]. Scientists have discovered that the cerebellum not only is implicated in sensori-motor function but also plays a cardinal role in the modulation of cognitive and affective processes. A “cognitive cerebellum” is identified in the posterior lobe, the dysfunction of which is at the base of the so-called cerebellar cognitive affective syndrome [22]. This is a new nosological entity introduced in 1998, more recently recognized as the third cornerstone of ataxology, together with cerebellar motor syndrome (CMS) and vestibule-cerebellar syndrome [23]. Nevertheless, the most significant aspect of Malacarne’s work was methodological, because it represented a systematic attempt to localize the intellect and the madness in the brain, unifying physical and moral, as well as physiological and psychological dimensions, establishing potentially quantifiable variations between the normal and the pathological [24]. The quantification was based on parameters such as cerebellar volume, weight, and number of folia. He quantified in 600 laminae the mean number for a normal cerebellum, above which the intelligence could be affected. Malacarne proposed to use also a new instrument, the “cefalometro,” to calculate the proportion between the size of the skull and the volume of the brain, because he supposed that an insufficient volumetric grown of the skull could block the development of the cerebellum, affecting the degree of intelligence [19]. By this approach, it could seem that Malacarne anticipated the idea of Franz Joseph Gall (1758–1828), father of phrenology, according to whom there was a one-to-one correspondence between well-circumscribed areas of the brain and intellectual or emotional functions. However, Malacarne was quite doubtful about Gall’s theory, of which he questioned many imprecisions, in particular from an anatomical point of view [25]. There were not at all or at least not enough proofs for any of the anatomical seat mentioned by Gall, that this seat performed exactly the function advanced by him [26].

At the end of his life, Malacarne had led down experimental foundations of a project on the recording of brain electricity [27]. He pointed out a metaphor comparing the structure of the human brain with Volta’s galvanic pillar. Between his first researches on the morphology of the cerebellum and this article, Malacarne moved from anatomical studies to experimental considerations on the origin of animal electricity. Therefore, he also contributed to the emergence of a new science, namely electrophysiology.