Mass, volume and dimensional distributions in biology, with special reference to cells.

The positively skewed distribution of mass (weight) in biology was examined, and it was concluded all weight or masses can best be described by lognormal theory. Examples are given ranging in weight from viruses to humans. The accretion of mass proceeds as "more of the same" and primarily does not alter function. Immunologic properties must be carefully preserved. Small biologic entities can afford only small mass gains or losses while preserving their functionality; the larger the entity, the larger is the variability of mass functionally permitted. A well-established, convenient graphic method of analyzing a sample is described, with the advantages and pitfalls discussed. At the cellular level, volume and dimensions are lognormally distributed whenever the specific gravity (g/cu cm) is nearly homogenous among the particles or cells. In multicellular organisms, dimensions and forms (such as height and cranial circumference) are primarily the product of multifactorial genetic determinants and frequently appear as normal distributions. This paper discusses the meaning of the law of proportionate effects for small biologic objects, especially cells, and how an initial or "elementary" distribution may be conceived.