Neuroglial Ontogeny

Abstract

The original concept of neuroglia meaning “nerve glue” was based on Rudolf Virchow’s assumption that there must be a mesodermal connective tissue element of the nervous system (Virchow, 1846, 1858, 1867). Even if neuroglial cells did not exist Virchow would have had to intent them as a requirement for his theory — as a bold conjecture thrown out for refutation. But techniques were inadequate to either corroborate or refute that conjecture. the mesodermal origin of neuroglial cells continued to receive corroboration (Andriezen, 1893; Weigert, 1895; W. Robertson, 197, 1899, 1900a) in the face of strong conterevidence showing that both neurons and glial cells originate from embryonic ectoderm (His, 1889, 1901).

On a perfectly translucent yellow field appear thin, smooth, black filaments, neatly arranged, or else thick and spiny, arising from triangular, stellate or fusiform black bodies! One might say they are like a Chinese ink drawing on transparent Japanese paper. The eye is disconcerted, so accustomed is it to the inextricable network stained with carmine and hematoxylin which always forces the mind to perform feats of critical interpretation. Here everything is simple, clear, without confusion... The technique of dreams is now reality! The metallic impregnation has made such a fine dissection, exceeding all previous hopes. This is the method of Golgi.

Ramón y Cajal (1852–1934), Histologie du système nerveux, Vol. 1, p. 29, 1909

I have for this young researcher [Ramón y Cajal] the greatest regard, and as I have admired his great activity and initiative, I can appreciate the importance of his oiginal observations. The small differences between his conclusions and my own cannot have an effect on my sentiments, as I am profoundly convinced that such divergence, by which one can push research forward, is always useful to science.

Camillo Golgi (1843–1926), La rete nervosa diffusa degli organi centrali del sistema nervosa, 1901