That treatment with ionizing radiation will produce chromosomal rearrangements has been recognized ever since the classical study in Drosophila by Muller and Altenberg (1928). Studies in which treatments with ultraviolet irradiation and X-ray irradiation have been compared for the production of translocations have shown that ultraviolet irradiation produces fewer translocations than x-ray irradiation (Stadler and Sprague 1937; Stadler 1941; Emmerling 1955). In the micro-organism Aspergillus nidulans, a high frequency of chromosomal rearrangements (translocations) was round to be induced by gamma-irradiation (Tector 1961).

The study of the biochemical diversity or organisms as an aid to their taxonomic and phylogenetic classification is a comparatively recent innovation in biology. Since there are many natural chemical constituents present in plants which may be used in systematic studies many techniques for their analysis have been devised. The advent of paper chromatography in 1944, followed by the development of such techniques as electrophoresis, thin layer chromatography and gas chromatography, which enables the separation of a wide range of compounds in a relatively short time, has removed the difficulty of isolating many biochemical compounds which had been the main drawback to this type of study in the past.

The purpose of this thesis is to introduce a new mathematical approach to the study of evolution by natural selection. Practically all of contemporary mathematical evolution theory is encompassed by the field of population genetics, which takes the empirical facts of Mendelian genetics as given and infers their evolutionary consequences. The writer has approached the subject from the opposite direction. This thesis takes the occurrence of evolution by natural selection as a given fact, and emphasizes that mere chance could not have produced the highly adapted organisms we see around us within the limitations of time and space to which natural selection has been restricted. It then attempts to infer the properties of a genetic system, and other conditions, which are necessary and sufficient to allow natural selection to have yielded products so different from those which would have been yielded by chance alone.

Note: Missing Page 135. / One of the main unsolved problems of medicine today is the fact that the frequency of human congenital malformations has shown no reduction in spite of the recent spectacular advances in understanding and treatment of human disease. The twentieth century has seen the successful application of the Mendelian laws to problems of disease transmission in man, leading to the brilliant elucidation of gene action in biochemical terms exemplified by the inborn errors of metabolism (Garrod, 1923) and the abnormal hemoglobins (Ruchnagel and Neel, 1962) and the development of refined methods to study the morphology of human chromosomes, leading to the identification, within the last few years, of a new group of human diseases, the chromosomal aberrations.

Although genetic studies are devoted, for the most part, to characters showing clear cut segregation, a great many genetically determined defects show familial patterns which cannot be explained by a difference at a single genetic locus or even a very few loci. These defects are often biologically important and, in spite of the difficulties involved in their analysis, deserve more intensive study. The studies which have been done, such as those of Wright (1934a, 1934b), Reed (1936), Gruneberg (1952), Lerner (1954), and Landauer (1957), attempt to explain the apparently non-Mendelian behaviour of the trait in question by invoking either reduced penetrance or multigenic inheritance, or both.

Although the fact that man might produce malformed offspring in animals by altering the maternal environment was stated in the Bible (Genesis 30), when Jacob caused Laban’s sheep and goats to have striped and speckled young by holding striped rods in front of the females at the moment of conception, experimental teratology is a relatively new field. Hale, the first scientific mammalian experimental teratologist, produced a litter of 11 eyeless pigs by feeding the mother a vitamin A deficient diet (1933). At the present time most teratologist, have progressed from merely producing malformations and enumerating them, to making use of the malformations for the study of their pathogenesis and the role played by the genetic background of the mother and embryo in the production of the malformation in question.

Ragweed hay fever makes thousands of people miserable every year. These people have an allergy to ragweed pollen. The characteristic symptoms include rhinitis, sneezing, nasal blockage and itching of the nose, eyes and throat. These symptoms appear in sensitive people soon after ragweed pollen is introduced into the environment. They occur every year from about the middle of August until the first frost, during the time that the wind-pollinated plant is dispersing its heavy load of pollen. The plants causing most trouble are the short ragweed, Ambrosia artemisiifolia L. var. elatior (L.) Descourtils, giant ragweed, Ambrosia trifida L., and western ragweed, Ambrosia psilostachya DC. var. coronopifolia (T. & T.) Farw. (Bassett and Frankton, 1961).

Although abnormal development has fascinated man from very ancient times, it has been only within recent years, as the management of nutritional and infectious diseases has been increasingly perfected, that critical attention has been given to human teratology. This increased interest has stemmed chiefly from the practical problems with which the obstetricians (Davis and Potter, 1957) and pediatricians (Warkamy, 1957 b) must deal and from the concern in this "atomic age" with radiation effects on gene mutation rates and on prenatal development (British Medical Research Council, 1956; National Academy of Sciences - National Research Council, 1956).

The skin and its appendages in mammals provide an excellent medium for investigating the effect of experimental procedures on the development and morphology of a specific integrated system. Many mutations which affect the piliary system are known in various species of mammals (David, 1932; Thigpen, 1951). [...]

With the progress or civilization agriculturists have been asked to provide the population with more and better food. Accordingly, attention has been directed not only to those crops which can be used as an immediate source or food but also to those which only serve to provide fodder for domestic animals. Red clover is a plant of the latter type. The intermediate climatic zones of the Eurasian and North American continents constitute the main areas of distribution of red clover.