| Popis: |
Malpighi’s perception of tightly packed glands in the cerebral cortex is usually considered to be a major mistake by him, and caused the widespread criticism of microscopy and its replacement by injection technique. The eclipse of the microscope ensued until it was rediuscovered and triumphed in the 19th century. One cannot simply disparage Malpighi’s studies in the central nervous system, however. Of course, there are flaws in his description, especially in considering the cortex of the spinal cord identical to that of the brain. On the other hand, there is something alluding to the connection between neuron and axon, just as in Golgi 200 years later. The exploration of human brain remained a very difficult task until the 19th century, because of its extremely difficult preservation at autopsy. For instance, the temporal lobe was described only in 1584, when Giulio Cesare Aranzi (1530-1589), from the Bologna University, produced the first description of the hippocampus. Therefore, Malpighi appears to be the most audacious scholar in delving in the human brain in depth. He was not alone, however. Niels Stensen (1638-1686), better known as Nicolaus Steno, decided to migrate to Tuscany. There, he started working in touch with Malpighi and other very interesting Italian scientists: Stefano Lorenzini (after 1652- after 1721) and Lorenzo Bellini (1643-1704). Like Malpighi, his friends made a large use of animal dissection, because of their easier availability and preservation. They were especially concerned with the central nervous system of sharks, because of its minor complexity. An interesting result consisted in the first demonstration of the electrical organs of torpedo. However, Lorenzini’s ampullae appear to be the most interesting and enduring discovery by the group of Malpighi’s friends. They appeared as a sort of complex cutaneus glands (in accord with Malpighi’s definition of glands) concentrated in the head of sharks. Modern neurophysiologists established their relevance in perceiving the variation of electric fields generated by swimming animals. Very recently a study re-evalueted the experiences by Malpighi’s friends in showing the very effective sensory coordination in sharks. |
