The shortage of edible oils and fats during the Second World War stimulated research in this laboratory on the utilization of linseed oil for edible purposes. This oil is available in good supply. Unfortunately hydrogenated linseed oil when incorporated into shortenings exhibited a marked tendency to produce off-flavours. This tendency to flavor reversion has been attributed to the isolinoleic acids produced by hydrogenation from linolenic acid present in large quantity in linseed oil.

The most widely used colorimetric method for the determination of pteroylglutamic acid (PGA) in pharmaceutical preparations is that developed by Hutchings et al. (1947). This method is based on the colour reaction for free amines as reported by Bratton & Marshall (1939). Various modifications of this method have been suggested but all of them may be criticized on similar grounds. In order to apply the procedure, a sample must contain at least 2 per cent PGA. Interference due to ferrous sulphate and liver concentrates must be removed.

Thermal treatment of linseed oil for the purpose of preparing non-reverting shortening from hydrogenated linseed oil was originally stimulated by the shortage of vegetable oils for edible use during 1939-45. The tendency to flavour reversion of hydrogenated linseed shortening has been attributed to the isolinoleic acids formed from linolenic acid during hydrogenation. On the hypothesis that linolenic acid reacts preferentially in thermal polymerization, it seemed that it might be feasible to reduce the linolenic acid content of the oil by a preliminary thermal polymerization before the hydrogenation.

The importance of phosphorus agriculturally, bas become commonplace to agriculturists. The functions, role, and forms of this element in soil have received favourable attention; yet, despite searching investigations there is still much lacking in our knowledge which would enable a better solution to agronomic problems. The inorganic forms of phosphorus have received the widest of attention, and though most have neither been isolated nor indisputably identified, there is, however, evidence as to the type of compounds (28) present in soils. Due to the greater complexity of organic compounds of phosphorus, they have not received adequate attention.

In 1947 an investigation on soil genesis was initiated at Macdonald College with the objective to obtain information on the mechanism of translocation within the profiles of forested podsolic soils of elements such as iron and aluminum.

One of the chief characteristics of podsol soils is the accumulation of organic matter and sesquioxides in the B horizon of these soils. In recent years several workers have studied characteristics of soluble organic matter leaching from the overlying organic layer of these soils and passing downward through the profile. However, it has not been established that these organic materials or any part of these are deposited in the B horizon of podsol soils, or if the organic matter leached from the organic layer in aqueous solution is similar in nature to the organic matter deposited in the B horizon.

Studies on the effects of exogenous hormones have led to the accumulation of a considerable body of information on the reproductive physiology and endocrinology of birds, and of the female domestic fowl in particular. Exogenous estrogens have been shown to produce striking effects in immature pullets, both on the morphology of the secondary sex organs and on the composition of the blood and other tissues. The similarity of these changes to those which occur in the normal pullet at puberty clearly indicate the presence of an endogenous estrogen or estrogens in the bird, and crude extracts of the ovaries of hens have been shown to have estrogenic activity by bioassay in rats.

This thesis describes an investigation of the forces causing swelling of Ca-montmorillonite clay in water and salt solutions. Studies on swelling of clay can yield results which are of value to a basic understanding of the behaviour of clay under compression. While the following experiments deal primarily with montmorillonite, most of the concepts will hold for any swelling clay. Good agreement of measured swelling with swelling calculated from osmotic forces of repulsion has been obtained for montmorillonite saturated with monovalent ions, the lack of agreement when the ions are divalent raises interesting questions.

For many years chemists have endeavored to evaluate soils for agricultural purposes and to determine fertilizer needs for maximum crop returns by chemical analysis of soil samples. More recently, attempts have been made to establish "critical levels" of the mineral elements necessary for normal crop growth in various organs of the plants themselves. Both of these procedures have met with some degree of success, but much work remains to be done in standardizing the methods, particularly those of the latter group, against field performance. [...]

The physico-chemical changes that take place during the coagulation of milk by the enzyme rennin are not fully understood. Aside from such factors as calcium ion concentration, temperature, and pH, the peculiar constitution of casein is also believed to play a major role in the coagulation process.