Avda. Doctor Arce, 37. 28002. Madrid (Spain)


The Cajal Legacy

The Instituto Cajal of the CSIC houses the Cajal Legacy consisting of all the belongings that Santiago Ramón y Cajal, by testamentary disposition, wanted to be kept in what was his Institute, after his death in 1934.

The original legacy has been completed and expanded by materials from Cajal's disciples (Spanish Histology School) and other scientists of the Institute.

The importance of this legacy lies in its status as a cornerstone of the discoveries and theories that have contributed to the development of knowledge of the human brain. Cajal's discoveries continue to have great repercussion and influence among the current scientific community, and these archives are essential to study the history of the discoveries and theories that have led to the current knowledge of the human brain in its double aspect: anatomical composition (individual cells) and physiological properties (formation of circuits and propagation of nerve impulses).


A unique documentary collection

Consisting of scientific drawings and manuscripts, histological preparations, anatomical paintings, photographs and microphotographs, the Cajal Legacy constitutes a unique and highly valuable documentary collection..

Apart from the purely scientific collection, there are also portraits and photographs of Cajal's daily life, paintings and artistic drawings, personal objects and laboratory apparatus. It also includes his correspondence,correspondence between members of the Spanish School of Neurohistology and other national and international scientists, an extensive bibliographic collection and the awards received by Cajal throughout his life, including the Nobel Prize in 1906.

The scientific archives of the Cajal Legacy belong to the Census-Guide of Archives of Spain and Ibero-America, which since 2017 has been included by UNESCO in the Memory of the World International Register of the World Heritage as part of the inscription 'Archives of Santiago Ramón y Cajal and the Spanish Neurohistological School'.

An essential archive for the history of Neuroscience

Juan A. de Carlos. Responsible for the Cajal Legacy


Cajal's artistic abilities are reflected in his scientific production. The Aragonese scientist had a masterly ability to capture on paper what he saw through the microscope. Although Cajal's histological drawings are made on low-quality paper, they are true works of art in small format, due to the fidelity with which they show the tissues they represent..

Drawn with graphite pencil and later painted with India ink, Cajal's illustrationsrepresent three-dimensional structures that help us understand the complexity of brain structures. Only a few are colored. These pieces are true jewels for both the scientific and artistic true jewels for both the scientific and artistic communities, due to the beauty of the compositions and their similarities to nature.


Cajal was a great lover of photography. He developed his own developing solutions and was a pioneer in photographic coloring techniques in Spain. He did research on photographic emulsion techniques, which he applied to the improvement of Edison's gramophone, although he could not go deeper into them due to lack of means and technical personnel.

In 1890 he was appointed honorary president of the Royal Photographic Society of Madrid. He would take photographs of family, travel and everyday life. His passion for this discipline led him to publish in 1912 a treatise on photography entitled "La fotografía de los colores. Bases científicas y reglas prácticas" where he theorized about his research on the treatment of photographs to add coloration to them.He was also a pioneer in the use of photomicrography, taking photographs with the use of a microscope.

The collection of stereoscopic photographs printed on glass plates is vast and of great value both scientifically and artistically, and their contributions to this field are fundamental to the technical study of photography..

Histological preparations

The histological preparations are another of the great jewels of the Cajal Legacy.

Thanks to their optimal state of preservation, they can still be used today, becoming windows into the microscopic world of nerve tissue that served to create the 'Doctrina de la Neurona'.

Piezas del archivo

The Cajal Legacy, inventoried in 2008, consists of a total of 28,222 objects:

  • Photographic archive (2,773 items)
  • Precision scales (2)
  • Photographic cameras (5)
  • Correspondence (2,584)
  • Ceramic (2)
  • Dyes, Reagents and Solutions (387)
  • Notebooks (11)
  • Scientific drawings (1.976) by Cajal (1.800) and his disciples
  • Artistic drawings (2)
  • Diplomas and certificates (109)
  • Sculptures (6)
  • Phonographs (1)
  • Books, newspapers and magazines (7,000)
  • Manuscripts (1952)
  • Gas lighters (3)
  • Medals, decorations and awards (25)
  • Optical microscopes (21), boxes (5) and microphotography devices (1)
  • Microtomes (3)
  • Furniture (20), including work table and chair, chemical preparation cabinets and display cabinets
  • Straight razors (9)
  • Personal belongings (15), including his last glasses, wallet, walking stick, passport, identification card, professor's robe and camera with bellows
  • Paints (10)
  • Histological preparations (17,150, of which 3,000 are Cajal originals).
  • Projectors (4)
  • Telescope (1) used by Cajal in his researches
  • Textiles

The Cajal Museum

During the Spanish Civil War (1936-1939), the Cajal Institute was bombed and part of it was destroyed. Francisco Tello and Fernando de Castro ensured that the center was not looted during the unrest of the conflict.

In 1945, the Institute was reopened after the reconstruction of the damaged areas and the creation of new departments. In addition, a museum was created to guard and exhibit Cajal's legacy. All the pieces (photographs, drawings, manuscripts, laboratory material, etc.) were part of the first Cajal Museum. The management of the center was carried out by the members of the center, without receiving any funding from the State.

With the transfer of the Cajal Institute to its current headquarters on Avenida Doctor Arce in Madrid and the laboratory extensions carried out in 1989, the museum collection was relegated to a small display located in the center's library, where a very limited and careful selection of historical pieces is exhibited, recreating Cajal's workplace with some of his original belongings.

The rest of the assets that make up the Cajal Legacy are protected and conserved in a secure room with controlled humidity and temperature, while awaiting an appropriate exhibition space so that all of it can be exhibited in a future national museum dedicated to the figure of Santiago Ramón y Cajal and the Spanish Neurohistological School.

Recreación del despacho de Cajal en la biblioteca del Instituto

The permanent exhibition of the Cajal Legacy in a stable national museum is a demand of the Cajal Institute, Spanish society and the international scientific community, who have been insisting for decades on the need to preserve and disseminate the value of the research work of Santiago Ramón y Cajal and of those scientists who, in truly precarious conditions, managed to put our country at the top of the world scientific map.

The future National Museum of Cajal and the Spanish Neurohistological School would also serve as a reference center for the interpretation and teaching of the history of Spanish neuroscience which, in short, is the history of neuroscience worldwide, since thanks to Cajal and his disciples, Spain was a pioneer in the study of the brain.

Semi-permanent' exhibition at the MNCN-CSIC

Since November 2020, the National Museum of Natural Sciences (MNCN-CSIC) is hosting a 'semi-permanent' exhibition on the Cajal Legacy.The exhibition, which occupies an area of 120 square meters, displays more than a hundred carefully selected pieces including twelve original drawings, the Nobel medal and his first laboratory diary.

The exhibits include oil paintings, photographs, drawings, laboratory material, instruments, scientific notebooks, awards and distinctions, as well as a set of personal objects and non-scientific books that show the humanistic facet of the genius from Petilla de Aragón.

The sample collected for this exhibition is a small example of what could be, in the future, the monographic museum dedicated to the father of Neuroscience and the Spanish Histological School. A museum that deserves the most relevant figure of Spanish science and that would finally fulfill the desire expressed by Cajal himself to preserve his scientific legacy in his own Institute, and the intention of his children to turn it into a museum that would serve as a teaching and stimulus for future generations.

Information and inquiries

For further information, inquiries, requests for reproductions, management of reports or arranged visits (on an individual basis and for scientific purposes only), please contact Professor Juan Andrés de Carlos, head of the Cajal Legacy:

Contact the Cajal Legacy