Reading good old stuff sometimes pushes you to the borders of your knowledge. So far, I’ve been learning about Liesegang rings recently. No, nothing close to blingy blingy gangsta jewelry actually. Something that has more to do with chemistry. Liesegang rings are a phenomenon of periodic precipitation resulting in circular patterns that impressed scientists a lot a while ago, to the point it came out not only as a physico-chemical process, but as an explanation for some biological phenomena as well. As far as I can tell read, no unifying grand theory of this Liesegang phenomenon made it completely yet, chemically speaking. The thing is, with regard to biology, it did not really stand as a process of any explanatory power, and it disapeared from the biological jargon.
But which kind of biological feature could result from such a process as periodic precipitation? Guess it! It’s this rather intriguing organization of fruiting bodies in molds. Somewhat concentric circles. Striking regularity. In case you don’t see what I mean, and wouldn’t play the “wait and see” game, here what I found at the bottom of a long lost cup of coffee. (Hum, this coffee is not green, but it’s sure alive!).
The fascinating and familiar concentric distribution of fungous fruiting structures and the alternate concentric zones of dense and less dense mycelial aggregates have been many times reported in the literature but the data concerning the elusive factors which control them are too fragmentary and inadequate for a general theoretic treatment. I t may be possible to relate the chemically produced Liesegang rings to the analogous appearances in fungi and other organic forms and to apply the explanations given for the Liesegang phenomena to the fungi. (Hein, 1930)*
There was an age in biology where a great hope was given to the “life as a crystal” concept. Biological organization and structure, or say, even development, had to be explained, and nothing would have made more sense than simple universal rules. It’s not that far ago, and it’s impressive how deeply this was in the airs and the minds. And I’ll let you discover the following ending paragraphs of this old paper:
Symmetry was recognized as an aesthetic principle by the ancients and its importance in art is everywhere known. The beautiful many-times figured radial and zonal patterns in fungi owe their aesthetic value to their symmetry. The widespread application of this principle in science generally has been most effectively pointed out by Jaeger (1920). In the structure of atoms in the molecule, the forms of crystals, the arrangement of leaves and branches, of floral organs, and of organic cells; everywhere the principle of symmetry finds expression. That radial growth may be due to morphaesthesia has been earlier pointed out (Koll, 1900; Hein, 1928). Symmetry may be thought of as an expression of morphaesthesia and since symmetry in organisms has often been shown to be the result of surface tensions (Thompson, 1917) or form tensions (Kiister, 1913) all symmetry relations may possibly be traced to this force. Millis (1918), in pointing out the importance of “the simple geometrical principle, ” raises the question whether “all life, growth, repair, decay, and dissolution: even all mind, intelligence, emotion, and all reasoning and thought” may not be intimately related to it.
Oh my, mind! So far. Though this might seem today a long way past, I like the passionnate tone of this old paper. There’s something about doing science that can’t be missed here: at some point, an idea will give you this wonderful feeling that you got it. And you’ll be… enthusiastic is not even strong enough. And it’s worth all the hard work you’ve gone through until everything becomes clearer.
* Illo Hein (1930). Liesegang Phenomena in Fungi.
American Journal of Botany, 17 (2): 143-151.