Little Santiago Ramón y Cajal was a restless and mischievous child. It is well known that his childhood was spent in the high Pyrenees of Huesca, where his father worked as a doctor. Santiago had a passion for nature and the fact of having grown up in this privileged environment helped him perpetuate this love for the world around him. Ayerbe, the little town where he grew up, was witness to this. The boy Santiago spent breaks at the Jesuit school in Jaca looking around him, looking for any hint of life that moved among the weeds of the patio. Between games, he always took time to notice the invertebrate creatures that tried to hide from the children. As he grew older, he changed the games with his friends for fooling around with the girls and the teenage talks at the Huesca institute, but when he went out for recess he always found time to continue scrutinizing the nature that was bustling around him or to look at the sky and enjoy the flight of birds.
He had an immense passion for birds . This was such that he took advantage of the spring to make a census of the nests he found in his environment and had them perfectly located and cataloged by species. At the age of thirteen, he began to collect eggs that he kept in a box conveniently separated by compartments and labeled, with the idea of being able to obtain chicks of the different species collected. He even paid friends and farmers in the area with one frame coin (equivalent to eight maravedís) for each nest they pointed out to him. In this way, he came to collect more than thirty eggs of different species , which unfortunately were spoiled due to the rigors of summer. Most of the eggs rotted or broke. At that moment, young Santiago understood the damage he had done, depriving those potential chicks of being born, due to the collector’s desire that any naturalist can hardly escape. That failed experiment with its compartmentalized box and rotten eggs would undoubtedly mark the feelings of the adult Santiago, who always kept in mind his intention to harm the object of his research as little as possible , even more so if it was a living being.
naturalist vocation
Returning to that spring, we will say that some specimens of nightjars, sparrows, thrushes, finches, larks, wagtails, blackbirds, herons, goldfinches, cuckoos, nightingales or quail did not hatch, but a feeling of protection and clemency towards the natural world that would accompany him throughout his life. He was horrified when he saw other children playing to harm animals, he suffered when he saw his friends torturing living beings , because he preferred to enjoy watching them. In fact, when he caught one, he always looked for a way to do it so that they suffered as little damage as possible, devising ingenious and non-damaging traps. In this way he caught little birds that he cared for carefully, to observe them in amazement and then release them when he could no longer attend to them.
He himself relates with immense passion how he marveled at the incubation and hatching of the chicks, the metamorphosis of the young into adults, the appearance of feathers, the clumsy flapping of the fledglings and the first flights that freed them from their earthly bonds. It is clear that while he reveled in these details, he distanced himself from other children who captured them for gastronomic interest or for the simple vanity of the hunter. Little Santiago was far above it, since the naturalist’s instinct for observation and curiosity was strong in him.
His animal experiments
Santiago grew up and studied medicine in Zaragoza, later enlisting as a military doctor in the war in Cuba, from where he had to return when he contracted malaria and dysentery. It was then that he began a prolific research career. Like his little birds, little Santiago had already taken flight like Don Santiago Ramón y Cajal. His research vocation developed with great force from 1875, even leading him to build his own first microscope with which he would begin to observe and investigate both organisms and tissues. Working at the Hospital Nuestra Señora de Gracia in Zaragoza, he dedicated himself intensely to histological research that would bring him so much joy and that would take him down to posterity as one of the first and great connoisseurs of the human brain.
His “neuron doctrine” and his detailed drawings of the cells that make up the nervous system are well known, but his experiments on animals are less so. Don Santiago Ramón y Cajal experimented on some fifty different species of animals—many of which were invertebrates—which he observed using his home microscope. The fact of observing the nervous structures in simpler animals and in more complex animals made it possible to have a very important comparative sample of how the connections between the elements of different types of nervous systems are established. Which was a genius comparable to the fact that he used not only the brains of adult animals for his experiments, but also the brains of embryos and offspring . This brilliant idea also allowed him to study how neurons grow and develop, in addition to being able to see how the connections between them are established.
The «animal invertebrate laboratory»
He had in him representatives of different phyla. Among them were seven specimens of leeches and four earthworms , both representatives of the annelids, a group commonly known as worms. He also had in his “animal invertebrate laboratory” a few molluscs that were the object of his study, namely four snails, eleven cuttlefish and one squid . Being simple animals, he did not need to observe many more specimens. As for arthropods, it was not so much the number of specimens, as the variety of organisms observed. They were mostly insects : a beetle, six bees, a wasp, three crickets, a dragonfly, six flies and two grasshoppers. Surely to catch them he used some of the techniques learned as a child when he ran through the green fields around him. Crustaceans are also arthropods, and this group included seven crabs and three lobsters, plus a sand flea and a brown shrimp.
Not even the transition between invertebrates and vertebrates escaped the rigorous investigation of this famous scientist with the spirit of a naturalist, and among his observations are two specimens of amphioxus . These strange animals, also called acraniums or cephalochordates, live in coastal marine areas. They are beings that have been given great importance for having been considered the closest group to vertebrates or higher chordates. Few organisms as amphioxus present so clearly the four distinctive characteristics of chordates: presence of notochord, hollow dorsal nerve cord, pharyngeal slits and post-anal tail. The notochord and the nerve cord were undoubtedly a striking attraction for the researcher’s neurons, who did not miss the opportunity to study these curious animals.
studying vertebrates
The bulk of Ramón y Cajal’s animal laboratory was made up of species of vertebrate animals, among which there were also representatives of all classes, beginning with some species of fish ; specifically three specimens of trout ( Salmo trutta ) and three torpedos ( Torpedo torpedo ). He knew how to choose a representative species of the bony fish —with spines— and another of the cartilaginous fish.
Among the amphibians , he chose five newts ( Calotriton asper ) and seven gallipatos ( Pleurodeles waltl ), but the most illuminating results were provided by the two tadpoles and the twenty-one frogs ( Pelophylax perezi ) with which he was able to study the development of the nervous structures from the larval stages until they metamorphosed into adults.
A dozen lizards and another lizard, along with a turtle, a chameleon, a water snake and two land snakes represented the reptiles among the animals with which our Nobel Prize winner experimented, getting closer and closer to more complex nervous systems. Being aware of this increase in complexity, many birds were part of his research, and compared to all the previous groups, the number of specimens grew very significantly. One hundred and nine chicken specimens —because they were the most affordable—, served to have a precise description of the avian nervous systems, but it was not limited to chickens and he also experimented with twenty-six swallows, fourteen ducks, eight sparrows and eight nightingales, six hens , six passerines — unspecified small-sized birds — , an eagle, a partridge, a moorhen, a magpie and a greenfinch. He repeated the comparison between hatchlings and adults —as we have already mentioned what he did with amphibians— with six specimens of pigeons and six other pigeons, in addition to chickens and hens.
A special interest in mammals
But the bulk of his research was carried out, as expected, with mammals, the class of vertebrates to which our species belongs. In this group you could make the observations of nervous systems more similar to the human . One might expect that Don Santiago would limit himself to typical laboratory animals — rats, mice and guinea pigs — but he did not stop at them and many more mammals were studied. A large part of them was made up of the aforementioned triad, with one hundred and seventy-three mice, twenty-five rats and three guinea pigs, but the largest number of animals with which he investigated were cats, with a total of five hundred and forty-four specimens. In the saga of the cats were the rabbits, which were four hundred and twenty-five, followed closely by the dogs, these being two hundred and ninety-three specimens. He did not miss the opportunity to study large animals, such as the eighteen oxen, the fifteen cows, the two bulls or the five horses that were also study subjects. Again he also had the good idea to study a calf, to compare, with its corresponding adults. And how to leave out pigs , whose organs are so humanlike that they are ideal for xenotransplantation. Thirteen pigs were studied.
And we end this review of the animals with which Don Santiago Ramón y Cajal experimented in his laboratory with thirty-five monkeys , probably of the Macaca sinica species. Surely, Cajal’s nervous system shook from the brain to the spinal cord when he looked into the eyes of these apes or when he observed their incredibly human little hands. Undoubtedly, one cannot remain oblivious and cold in the face of the suffering of these creatures and despite the fact that he made an effort to respect all possible ethical questions regarding animal experimentation, our Nobel Prize winner was not oblivious to the suffering of creatures from his lab . It is known that he sometimes referred to them as «the poor victims of Science» .
Without a doubt, Don Santiago Ramón y Cajal was one of our most illustrious researchers, one of our best-known scientists, but deep down, and partly thanks to that, he never stopped being little Santiago, whose laboratory was his own. natural environment in which he grew up and grew up. That is why he never lost respect for his object of study , the animals, and that is because he never stopped seeing them as those defenseless little birds that died before hatching. Moreover, his admiration for them grew when, studying their nervous system, their neurons and their neural connections, he saw that they were so similar, or rather, so equal, to us humans.
