Archetypes and Symbolism

Abstract
The writer points out that apparently all teachers have a strong inclination toward simplification by use of symbolism, formulae, diagrams, and classifications. His main concern is with the application of these methods to 3 subjects in anatomy. The 1st cited resulted in the concept of the archetype vertebrata of Owen, initiated by Oken with his notion of the vertebral nature of the skull, and led to his more general idea that the entire skeleton is only "a ramified and repeated vertebra." The 2nd illustration of over-simplification and generalization is the conception of embryonic aortic arches as representing a supposed primitive state of which all modern adult conditions are modifications. In this the recapitulation argument seems unsound since at no time do all the arches really exist in the number and condition of the supposed primitive type. The 3rd example is that of the vertebrate brain developing from 3 primary vesicles. This conception, originated by Meckel and elaborated by von Baer, is likely based on the chick, so long almost the only form studied. Here the primordia of the large optic vesicles develop very early, and have been indicated as the midbrain, of which they really form a small part. Without these, however, it would be difficult clearly to recognize a genuine fore and hindbrain. In the supposed 3-brain vesicle stages of the mammal, moreover, it now appears impossible to discern any primary vesicles. In the central nervous system also, it is becoming apparent that there is no common archetype of which all more complex forms are elaborations. Thus, the author warns that symbols, diagrams, and other forms of simplification for teaching purposes should be used with discretion.