INSIDE A DNA

Though the human intelligence is so high as to explore into the interiors of a cell, and then into the various components of the cell, there is still so much yet to be explored!

A 3-D photograph of DNA molecules can be seen at
http://www.genomenewsnetwork.org/articles/2004/10/15/insidedna.php

Swammerdam developed the theory of preformation. Preformation” was a early theory of development, which flourished for over a century. It had its origins in one of Swammerdam’s most notorious experiments in which he dissected a silk-worm caterpillar and correctly showed the presence of structures such as wings, legs and antennae within its body, prior to pupation (this is true of all moths and butterflies).

As early as 1665, in front of a meeting of Thévenot’s circle (a predecessor of the French Académie des Sciences), he dissected out these structures, showing “a Butterfly enclosed and hidden in a caterpillar, and perfectly contained within its skin” as he put it, much to the amazement of his audience.

In the early 1670s, the Cartesian priest Malebranche popularised Swammerdam’s view by combining it with the mathematical idea of infinity recently developed by Pascal and the fact that, seen under the microscope, life-forms indeed appeared to recede into the infinitely small.

The Theory of Preformation:

The theory of preformation was enthusiastically accepted by almost all naturalists of the 17th and 18th century. Swammerdam, Leeuwenhoek, Leibnitz, Réaumur, Spallanzani, Boerhaave, von Haller, Bonnet and many other great scientists declared themselves convinced preformationists, and this not only for experimental reasons but mainly for theoretical ones. They did know the laws of geometrical optics and were aware that their microscopes were affected by aberrations, but the existence of living creatures that are invisible to the eye could not be disputed, and was leading to an extraordinary conclusion. The great idea of preformationism was the principle that the infinitely small is as real as the infinitely large, and this meant that it is always possible to explain living structures with smaller structures. Such a conclusion was indeed legitimate at the time, because there was no atomic theory of matter, but once again it was the microscope that decided its destiny.