Due to the relatively small amount of work concerning radiation, it was thought feasible to use ionizing radiation as a tool to study the relationship between water and salt flux in isolated root systems. Moreover, the more quantitative potometric method lends itself well to such a study, since the two processes can be followed simultaneously. the aims of this study, therefore, were 1) to determine effects of X-irradiation on water, calcium and potassium flux in excised onion roots; 2) to determine the dose levels required for producing permeability changes; 3) to investigate the nature of radiation damage to root systems; and 4) to attempt to shed light on the relation between water transport and ion movement in root systems.

The purpose of the present study of the herpetofauna was to obtain additional information regarding the vertebrates of Denton County, and to produce a well-preserved, cataloged collection of the amphibians and reptiles for the Museum of Zoology, North Texas State University. An understanding of the vertebrate life of the county also involves an investigation of the habitats within the county that may, in part, count for the distribution of these animals. It is well recognized that the environmental areas of the county have altered vastly during the last one hundred years. This alteration is due largely to agriculture and industry. However, there are adequate numbers of natural environments, as well as newly created ones that may contribute to the distribution of the vertebrates at the present time. Therefore, the problem not only concerned the collection of specimens, but also the identification, abundance classification, general habitat classifications, and county distribution.

Exactly where in the hypothalamus is the adrenal-pituitary response to X-irradiation "triggered" or initiated? Moreover, does ionizing radiation act directly on specific centers in the brain or does it act indirectly via the production of some humoral agents? Finally, what role does the hypothalamus play in the radiation-syndrome? The purpose of the present study was to attempt to answer these questions by determining the effects of two stressor agents, X-irradiation and electrical stimulation applied either singly or together, on the activity of the adrenal-pituitary axis. The parameters measured were changes in plasma corticosterone, in circulating eosinopihils, and in adrenal gland weight.

This thesis compares the specificity of passive transfer of chemical contact hypersensitivity following various methods of sensitization.

It is the purpose of this study to ascertain what environmental factors might cause morphological changes exhibited by certain algae, also to determine if this variation in morphology is vegetative, reproductive, or artifactual in nature, and to show what effects these changes in morpohology might have on classification of the organisms in question.

The purpose of this investigation is to attempt to learn something of the biochemical ecology of volatile substances produced by actinomycetes.

It is the purpose of this investigation to modify existing methods in an attempt to provide a rapid identification of members of the genus Streptomyces.

The purpose of this thesis is to report the interaction of aromatic hydrocarbons with DNA and to attempt to determine the relative binding affinities. The effect of the hydrocarbons on the continuity of the DNA molecule has been studied also and discussed.

This research was undertaken primarily to further elucidate the life history of this medically important spider. Special attention was given to rearing experimental spiders under as near-natural environmental conditions as possible.