Ralph C. Ballard

Variation Principles and Applications in the Study of Cell Structure and Aging

In the search for general trends and laws in Nature, there is a tendency to exorcise variation as an artifact, for which imperfection and inaccuracy of observation are held responsible. However, there is often a residual variation and unpredictability when measurement error and external uncontrollable disturbance (noise) have been effectively removed. The following principle can be stated: Variation is an inherent characteristic of objects and systems—be they cells or organisms, cities or countries, rocks or mountains, electric bulbs or airplanes—a consequence of the statistical (macroscopically apparently nondeterministic) nature of the processes by which the objects and systems are formed (or manufactured) from simpler elements.

An intracellular study of the myocadial cells of the flesh fly, Sarcophaga bullata☆

Abstract 1. 1. The myocardial cells of the flesh fly, Sarcophaga bullata , have been studied using conventional micro-electrode techniques. These studies indicated that an initial period of aertation or oxygenation was necessary to maintain the heart. 2. 2. The range of values, for the action and resting potential were 45 ± 8 mV and 57 ± 11 mV respectively with negligible or no overshoot. 3. 3. These studies indicate that the intracellular potentials from the myocardial cells of the flesh fly can vary in amplitude, rate and duration from cell to cell and within the same cell. 4. 4. The wave form is complex and commonly shows pacemaker characteristics as well as fast spikes which suggests a neural involvement.

The determination of ribose nucleic acid in the heart and associated tissues of house flies of various ages

Abstract 1. 1. Cardia RNA levels and dry heart weights were determined for male and female house flies of various ages. Mean RNA values for all organisms were 0·584 μg RNA per heart and 0·0388 g RNA per g of dry tissue, while mean heart weight was 15·03 μg per heart. 2. 2. RNA expressed in terms of dry tissue weight did not vary significantly within a given sex at any age or between the sexes at any age. 3. 3. Heart weight and RNA expressed in μg per heart did not vary significantly with age for females; however, these values decreased for males in the oldest age group studied.

DNA in the heart of male and female house-flies of different ages☆

Abstract 1. 1. The amount of deoxyribonucleic acid was determined in the heart and the associated tissues of adult Musca domestica L. 2. 2. The DNA analyses were performed by a microbiological method using Lactobacillus acidophilus ATCC 11506 and by the Burton modification of the Dische diphenylamine reaction. 3. 3. The average amount of DNA was found to be 0·367 μg/100 μg fresh tissues in the males, and 0·384 μg/100 μg fresh tissue in the females. These values were also expressed on a per heart and dry weight basis. 4. 4. The quantity of DNA in the hearts of the males and females of the same age group or of different age groups is similar. 5. 5. If DNA is considered an index to cell number, the cell number remains approximately constant for insects of different ages regardless of sex.