Classics in anatomy: Keith Porter's Harvey Lecture, “The Submicroscopic Morphology of Protoplasm”

Abstract

A sense of the excitement of exploration surrounds the beginning of any new endeavor. Anyone in science knows this from the experience of venturing into a new area of research, whether as a graduate student just starting out in the laboratory with a newly claimed project, or even as an established investigator whose work has just taken a different turn to lead in a new direction. This was especially true for those working with the latest technology in visualizing fine details of anatomical structure: the electron microscope. At its inception in the 1940s and early 1950s, anything seen with this innovative tool was new, and any descriptive study of cells and cell components at the ultrastructural level (or “submicroscopic,” as it was often known at the time) was welcomed as a valued addition to the body of biological knowledge. In the Classics in Anatomy article in this issue, Dr. Peter Satir introduces for us the reprinting of a lecture by one of the true pioneering giants of our anatomical field. Dr. Keith R. Porter was a leader in the use of the new electron microscope to probe deeper into the structures only hinted at by even the best light microscopes. In his 1956 Harvey Lecture, Dr. Porter focused primarily on acquainting his audience with two cellular structures that were, at the time, highly intriguing. One, the endoplasmic reticulum, held a special interest as his own area of specialty; he had published the first descriptions of the ultrastructural details of this complex structure whose very name was based originally on a misinterpretation of what was seen at the light microscopic level. He also presented a detailed account of the architecture and functionally significant variants of cilia. These cell specializations were noted in several examples of cell types, each with different details of structure related to the specific function needed for that particular cell, yet maintaining the requisite pattern of ultramicroscopic structure that defines the family of cilia. It is interesting to an anatomist of today to note that Dr. Porter pointed out at the beginning of his lecture that there was then a great deal of effort being spent on determining the chemical composition of biological materials, but that “relatively less attention and interest is being focused on the spatial arrangement of these materials in biological systems. This fact … must be regarded as unfortunate because we cannot hope to comprehend the activities of the living cell by analysis merely of its chemical composition of the properties of its component molecules” (Porter, 1957). He pointed out that the development of the electron microscope was timely in that regard, as it seemed to have the potential to bring the discoveries in physical and biological chemistry into focus in relation to the component structures. He predicted that this aspect of the new technology would “attract a large number of devoted users who will seek to relate the form and function of cells at the macromolecular level.” This is a worthy observation for our own time, as current research in a variety of aspects of cell and tissue development, differentiation, and functional controls seems to be drawing researchers back to the questions of how these functions relate to macromolecular and cellular structures. It is most appropriate at this time for us to present here a new opportunity to “hear” a lecture from one of the truly great figures in structural sciences, to revisit a bit about the beginnings of our understanding of cell structure and thus function. It is also appropriate at this time to call attention to our Classics in Anatomy feature and invite our colleagues once again to suggest key articles or essays in their various areas of special interest that could also be considered important to the anatomical sciences in a more general sense. The intent of this feature is to present articles, essays, and published lectures by acknowledged leaders in the biological sciences, which have appeared in the past in this and other publications. In some cases, these “classic” papers may not date from the time of a turning point in new technologies, but perhaps when they appeared the authors might have been playing key roles in enhancing our understanding in a subset of structural biology. In reintroducing these key articles, we perhaps also have an opportunity to present something about the personalities responsible for the represented works. We can once again (or, for some of our younger colleagues, perhaps for the first time) appreciate both the workers and their work, for its composition as well as its subject matter, for its scholarly style and tone; that is in part what makes them classics.