{
  "id": "pio-del-rio-hortega",
  "type": "entity",
  "name": "Pío del Río-Hortega (1882-1945) and the transplanting of the Spanish neurohistological school to Argentina",
  "summary": "The man who found the cells Cajal could not stain — microglia in 1919, oligodendroglia in 1921 — and correctly guessed what both were for. Cajal expelled him from the laboratory in 1920 and never conceded the second discovery in print. The Civil War drove him to Paris, Oxford and finally Buenos Aires, where exile became transfer: a replica of his Madrid laboratory, a journal at the University of Buenos Aires, and students who carried his method into the electron microscopy of the synapse.",
  "locale": "en",
  "tags": [
    "science",
    "neuroscience",
    "biography",
    "medicine",
    "argentina",
    "americas",
    "twentieth-century",
    "women-in-science"
  ],
  "relations": [
    {
      "rel": "related",
      "target": "duran-jorda-blood-transfusion-service"
    },
    {
      "rel": "related",
      "target": "ponseti-method-for-clubfoot"
    },
    {
      "rel": "related",
      "target": "santiago-ramon-y-cajal"
    },
    {
      "rel": "related",
      "target": "severo-ochoa"
    },
    {
      "rel": "related",
      "target": "margarita-salas"
    },
    {
      "rel": "related",
      "target": "carlos-juan-finlay"
    },
    {
      "rel": "related",
      "target": "fernando-de-castro-arterial-chemoreceptors"
    },
    {
      "rel": "related",
      "target": "nicolas-achucarro"
    },
    {
      "rel": "related",
      "target": "rafael-lorente-de-no"
    },
    {
      "rel": "related",
      "target": "spanish-flu-misnomer"
    },
    {
      "rel": "related",
      "target": "mujeres-de-la-escuela-de-cajal"
    }
  ],
  "questions": [
    "Who discovered microglia and oligodendrocytes?",
    "What was Cajal's \"third element\" of the nervous system?",
    "Why did Río-Hortega leave Cajal's laboratory?",
    "What did Pío del Río-Hortega do in Argentina?",
    "Did Río-Hortega ever win the Nobel Prize?"
  ],
  "claims": [
    {
      "id": "c1",
      "text": "Río-Hortega was born at Valladolid in 1882, graduated there in fine arts and then took a medical degree, and moved to Madrid in 1912 to work with Nicolás Achúcarro, from whom he learned the metal impregnation methods for staining tissue. He drew all his own figures, with either hand. It was with Achúcarro and not with Cajal that he learned the craft on which everything else depended.",
      "sources": [
        "boullerne-feinstein-2020-rio-hortega"
      ],
      "confidence": 0.9
    },
    {
      "id": "c2",
      "text": "Cajal had stained astroglia with unequalled selectivity in 1913 but could not resolve a further population of small, apparently process-less cells, which he named the \"third element\". By modifying the Golgi method to include silver carbonate, Río-Hortega made those cells visible and showed that they were two distinct types, not one: microglia, published in four consecutive instalments in the Boletín de la Sociedad Española de Biología in 1919, and oligodendroglia, published in the Boletín de la Real Sociedad Española de Historia Natural in 1921.",
      "sources": [
        "boullerne-feinstein-2020-rio-hortega"
      ],
      "confidence": 0.9
    },
    {
      "id": "c3",
      "text": "He also inferred what the two cell types did, and was right about both: phagocytosis for microglia, myelin production for oligodendrocytes. Microglia had been glimpsed before — Alzheimer among others had seen strange amoeboid cells in the late nineteenth century — but Río-Hortega's stain showed the same cell across its states, from resting and ramified to amoeboid and phagocytosing, which is what converted a curiosity into a cell type.",
      "sources": [
        "boullerne-feinstein-2020-rio-hortega"
      ],
      "confidence": 0.85
    },
    {
      "id": "c4",
      "text": "The relationship with Cajal was not a discipleship and did not end well. Río-Hortega moved into Cajal's laboratory in 1918 after Achúcarro's death, worked there two years, and was expelled in 1920 amid rising tension with members of the group; he then set up his own Laboratory of Normal Histology and Pathology nearby at the Residencia de Estudiantes. Cajal came to accept microglia, but conceded oligodendroglia only in a personal letter to Río-Hortega in 1929 — five years before his own death — and never in a scientific publication.",
      "sources": [
        "boullerne-feinstein-2020-rio-hortega",
        "nombela-2021-rio-hortega-women-disciples"
      ],
      "confidence": 0.8
    },
    {
      "id": "c5",
      "text": "He was nominated for the Nobel Prize in Physiology or Medicine twice, for 1929 and again for 1937, the first nomination citing his work on the histology and histopathology of the nervous system and specifically on microglia and oligodendroglia. He did not receive it. For a period the cells were known in the literature as \"Río-Hortega's cells\", and the first account of microglia in English was his own, published in 1932 in a volume edited by Wilder Penfield.",
      "sources": [
        "boullerne-feinstein-2020-rio-hortega",
        "nombela-2021-rio-hortega-women-disciples"
      ],
      "confidence": 0.85
    },
    {
      "id": "c6",
      "text": "The move to the Americas was flight, not opportunity, and the sequence matters. The Spanish Civil War broke out in 1936; coming from a liberal family, Río-Hortega left for the Pitié-Salpêtrière in Paris, moved on to the Nuffield Institute at Oxford in 1937 — where in 1939 he became the first Spanish scientist made Doctor Honoris Causa — and when the bombing reached Oxford he accepted an invitation to Buenos Aires, arriving on 28 August 1940.",
      "sources": [
        "boullerne-feinstein-2020-rio-hortega",
        "nombela-2021-rio-hortega-women-disciples"
      ],
      "confidence": 0.9
    },
    {
      "id": "c7",
      "text": "Argentina rebuilt his laboratory rather than merely hosting him. He had lectured in Argentina and Uruguay in 1925 at the invitation of the Institución Cultural Española de Buenos Aires; in 1940 that same body, with his former pupil Moisés Polak and his friend Bernardo Houssay — the future 1947 Nobel laureate — organised the move, and built a replica of his Madrid laboratories, opened in 1941 and named the Laboratorio Ramón y Cajal. In 1942 he founded the journal Archivos de Histología Normal y Patológica at the University of Buenos Aires, which ran until 1966.",
      "sources": [
        "nombela-2021-rio-hortega-women-disciples",
        "boullerne-feinstein-2020-rio-hortega"
      ],
      "confidence": 0.85
    },
    {
      "id": "c8",
      "text": "The Argentine years were productive to the end and short. In almost five years he produced twenty-two papers and a book, some written while hospitalised, working on the peripheral nervous system and on tumours of the nervous system and coining the terms angioglioma and neuroglioma. He died in Buenos Aires on 1 June 1945. When the Institución Cultural Española offered the direction of the Laboratorio Ramón y Cajal to Fernando de Castro, another of Cajal's disciples, he declined and stayed in Madrid.",
      "sources": [
        "nombela-2021-rio-hortega-women-disciples"
      ],
      "confidence": 0.85
    },
    {
      "id": "c9",
      "text": "The transfer outlived the man, which is the part of the story usually dropped. Among the disciples he recruited in Buenos Aires were Moisés Polak, José Manuel Prado, the Uruguayan Washington Buño and, last, Amanda Pellegrino de Iraldi (1917-2007), born in San Nicolás to Italian immigrants. She never co-published with him, but carried his neurohistological training into Eduardo De Robertis's group, where she helped identify adrenergic synaptic vesicles by electron microscopy and showed that different neurotransmitters coexist in the same synapse; she succeeded De Robertis as director of the Instituto de Biología Celular in Buenos Aires. Her pupil Claudio Cuello carried the line on to McGill.",
      "sources": [
        "nombela-2021-rio-hortega-women-disciples"
      ],
      "confidence": 0.8
    },
    {
      "id": "c10",
      "text": "Two cautions belong on this object. First, one of the co-authors of the Frontiers study relied on here is Río-Hortega's grandnephew, which the paper declares; its archival apparatus is drawn from the Legado Cajal, the Archivo Pío del Río-Hortega at Valladolid and the Archivo Fernando de Castro, but its framing is sympathetic and the confidences here are set accordingly. Second, nothing in these sources supports a claim that the Argentine school would not have developed without him — Houssay was already there and already eminent. The defensible claim is narrower: a specific technique and a specific research programme were carried from Madrid to Buenos Aires by a man who could not stay in Spain.",
      "sources": [
        "nombela-2021-rio-hortega-women-disciples",
        "boullerne-feinstein-2020-rio-hortega"
      ],
      "confidence": 0.85
    },
    {
      "id": "c11",
      "text": "His remains were returned to Spain only after the dictatorship had ended. At the beginning of the 1980s César Aguirre Viani, chair of histology at Valladolid, opened contacts in Argentina to repatriate them; the transfer took place in 1986, and the two people entrusted with receiving Don Pío at Valladolid were his niece and former collaborator Asunción Amo del Río and the Nobel laureate Severo Ochoa. He was buried in the Pantheon for Illustrious Men at Valladolid.",
      "sources": [
        "nombela-2021-rio-hortega-women-disciples"
      ],
      "confidence": 0.8
    }
  ],
  "takeaways": [],
  "faqs": [],
  "evidence_tier": "secondary",
  "evidence": {
    "level": "industry_observation",
    "source_types": [
      "paper"
    ]
  },
  "moat_flag": false,
  "winning_edge": "Río-Hortega is normally met, if at all, as a line in a microglia review — \"first described by Río-Hortega in 1919\" — with Cajal's name doing the work around it. Two things go missing in that compression, and both are documented: that he was not Cajal's student but Achúcarro's, was expelled from Cajal's laboratory in 1920, and got his oligodendrocyte conceded only in a private letter that Cajal never repeated in print; and that the last five years of his life were spent in Buenos Aires, where the Institución Cultural Española rebuilt his Madrid laboratory, he founded a journal at the University of Buenos Aires, and the students he trained carried his histological method into the electron microscopy of the synapse. This object states the cost with the achievement — exile, two failed Nobel nominations, a repatriation that had to wait forty-one years — and refuses the flattering version of the Argentine story that the sources do not support.",
  "confidence": 0.82,
  "last_verified": "2026-08-11",
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    "name": "Pío del Río-Hortega (1882-1945) and the transplanting of the Spanish neurohistological school to Argentina",
    "description": "The man who found the cells Cajal could not stain — microglia in 1919, oligodendroglia in 1921 — and correctly guessed what both were for. Cajal expelled him from the laboratory in 1920 and never conceded the second discovery in print. The Civil War drove him to Paris, Oxford and finally Buenos Aires, where exile became transfer: a replica of his Madrid laboratory, a journal at the University of Buenos Aires, and students who carried his method into the electron microscopy of the synapse.",
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    "citation": [
      {
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        "name": "History of Neuroscience I. Pío del Río-Hortega (1882-1945): The Discoverer of Microglia and Oligodendroglia",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC7580141/"
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      {
        "@type": "CreativeWork",
        "name": "Women Neuroscientist Disciples of Pío del Río-Hortega: the Cajal School Spreads in Europe and South America",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8143187/"
      }
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}