I just was reminded of the great Leonardo da Vinci the other day. A book entitled “La Musica Celata” has just been published in which the author, Giovanni Maria Pala, lays out evidence that a musical theme is embedded in Leonardo's painting of the Last Supper. That Leonardo was truly one of a kind! His drawings and paintings reflect such a keen sense of actuality and maybe more. I am a neuro-anatomist by training. I always admired realistic drawings of the human body. In my mind, Leonardo was the first modern anatomist.
I once could visit a traveling exhibit of his drawings and notes on human anatomy at the Philadelphia College of Physicians. Beside the very impressively detailed renderings of muscles and bones, drawings on the brain caught my eye. On one parchment (Fig. 5), a schema on how the brain may work was center stage. The ventricles, that is the fluid-filled cavities, were of utmost importance. In Leonardo's time, it was commonly accepted that our thoughts, our spirit, would travel with the juice in the ventricles. The nerve cells were discovered only centuries later. However, the Maestro was not going to be fooled. If you train your eye on the lower left corner of the parchment, you discover that what looks like a smudge is the faint impression of a more detailed drawing of brain structure. As if Leonardo tried to draw something as he saw it and then erased it. The other parchment (Fig. 6) shows his method of reproducing the shape of the ventricles by filling them with wax in the bovine brain. On this parchment, again the ventricles take center stage, Yet, on the right side there is another faint drawing. This time, the shape is distinct. You see a very realistic reproduction of the cerebral cortex with its sulci and gyri. Though it may seem human, it is most likely the cortex cerebri of a cow. Yes, also ruminants have a cortex with numerous convolutions. That must have caught the Maestro's eye. I can imagine that he mumbled to himself: ”Only shows the limits of inductive thinking. This proves that cortical convolutions are no key to intellect!” And all the world's cows must have agreed with a resounding:” Moo!”
If you like to see more of Leonardo's notes on human anatomy, check in a book like Leonardo Da Vinci on the Human Body. In his studies, Leonardo was constantly struggling with the unreal views of the day and with the actuality that he saw and could not help, but draw. He must have erased his impression of reality many times, because of his fear of the authorities. Dissecting bodies was forbidden. He wrote his notes on the parchments in mirror image to conceal his thoughts from the average person who may have betrayed him. But, then he could not efface his convictions entirely. In the end, Leonardo's perceptions of the brain were correct, and he stands tall today. What can we learn from this?
Trust your own eyes more than anything, particularly when the views of the day get in the way.