During recent years a large body of information has accumulated regarding the nucleic acids, not only from a standpoint of their structure and properties but also in relation to their functions in the cell. It is a well-established fact that those organs which are most actively engaged in protein synthesis tend also to contain relatively greater amounts of nucleic acids. A considerable amount of information is available concerning the nucleic acid content of the liver of rats of various ages and under various conditions. However, there is comparatively little information regarding the nucleic acid content of the liver of fowl. As the female bird approaches the laying period and the endogenous gonadal hormones come into play, one might reasonably expect to find a change in the protein synthesizing activity of the liver. During the course of the present study, therefore, an attempt was made to follow the normal changes in the proportions of nucleic acids in the liver of the fowl, including both males and females, from hatching until the beginning of full reproductive activity at twenty-five weeks of age. At the same time, a group of sexually immature pullets was treated with gonadal hormones in order to investigate as fully as practicable the possible effects of estrogens and androgens upon the amounts and proportions of liver nucleic acids in the fowl. It was hoped in this way to have observations on the normal bird which would be helpful in interpreting observations[...]

The insecticidal value of l,l,l-trichloro-2, 2-bis (p-chlorophenyl) ethane (DDT) was discovered in 1944. Since its introduction as an insecticide, DDT bas become very well known as a pest control in various parts of the world. The popularity ot DDT was greatly enhanced by the demands of the armed forces during the second World war. The introduction ot DDT resulted in a large number of studies on the toxicity of this insecticide to animals as well as to insects. Despite many intensified studies on the toxicity of DDT, its fate in the insect body has never been completely described. Several theories have been proposed to explain the mode of action of DDT in the insect. Most of these theories have been contradicted and none have been entirely satisfactory. Early workers attributed the toxiciy of DDT to certain structural groups in the molecule. Recent workers consider the size and shape of the molecule more important. An intensive study of the action of DDT on insects bas been undertaken by the Entomology Department at Macdonald College. It vas decided to use C14 labeled DDT in the following studies:- (a) Penetration of DDT into the integuement of the insect, (b) Translocation of DDT in the insect body, (c) Determination of the organs affected by the insecticide. With this end in mind radioactive DDT was prepared. The active molecule contained C14 at the point of attachment of the two p-chlorophenyl rings. [...]

The synthesis of labelled amino acids was undertaken at this laboratory with a view toward carrying out some metabolism studies on laboratory animals and experimenting with isotope dilution techniques in the analysis of biological materials. The long-lived isotope of carbon, C14, offered a means of labelling compounds for such studies without the disadvantage of changed chemical properties. This problem is often encountered when chemically inert radicals are used for this purpose. The essential amino acid, phenylalanine, was selected for the first synthesis, with the radio-active carbon in the carboxyl position.

The term “fixation”, as first applied in the field of soil chemistry, was in reference to the fixation of nitrogen, where in atmospheric nitrogen is converted microbiologically, or otherwise, to a form that can be utilized by plants. This process is obviously a beneficial one and is in no way comparable to the fixation that occurs when phosphorus or potassium is converted from the water soluble or the exchangeable form to the non-exchangeable state. Fixation, in the case of nitrogen, increases the supply available to the plant.

Research in this laboratory on the utilization of linseed oil for edible purposes, was originally stimulated by the shortage of edible ails and fats during the second world war. This research was concerned with overcoming the unpleasant odour and taste associated with linseed oil subsequent to hydrogenation. The tendency to flavor reversion has been attributed to the isolinoleic acid produced by hydrogenation from linolenic acid present in large quantities in linseed oil. A method of removing a portion of the linolenic acid was developed. It was suggested that thermal polymerization would involve primarily the linolenic radicals.

The importance of phosphorus in plant nutrition has been recognized since the middle of the nineteenth century, when the analysis of plant ash showed the presence of phosphates and other inorganic salts, and the use of phosphorus-containing manures and fertilizers in field experiments greatly improved crop yields. Since that time, particularly during the last fifty years, phosphorus has arrested the attention of soil scientists who have contributed greatly to our knowledge of it and its soil-plant relationships. [...]

Proteins may be hydrolyzed by the use of acids, bases and enzymes. The strong mineral acids are effective hydrolytic agents and under suitable conditions will lead to complete protein hydralysis. However, under conditions that will give complete hydrolysis of the protein, the amino acid tryptophane is destroyed and humin formed. Cystine and other amino acids are partially destroyed by acid hydrolysis.

Hemlock and beech leachates which had percolated through the forest canopy and through the organic layer and the A horizon of two podzol soils were studied. Evidence was obtained to support the view that the podzolization process is more active under a conifer (hemlock) than under a deciduous (beach) canopy. It was found that the organic matter in the hemlock leachates was similar to the organic matter deposited in the B horizon of the soil studied. A chemical fractionation procedure was developed which isolated, from both hemlock leachate and B horizon extract, a substance that was potentially active in podzolization.

The earliest studies of the avian egg-yolk protein appear to be those of Gobley and of Valenciennes & Fremy. These workers recognized the presence of a protein, which Dumas & Cahours named 'vitellin', in egg-yolk. The nature of vitellin was the subject of controversy for many years. Its content of phosphorus led Miescher to regard it as a nuclein or pseudonuclein. [...]

Avian reproduction is cleidoic. The ovum is of relatively enormous size and consists almost entirely of yolk material. It is surrounded by a complex of membranes comprising the albumen, the shell membranes and the shell. The significance of yolk and membranes for the developing organism has attracted close attention from the chemical embryologist, and the hen's egg has been his classical material as it has been the classical material of embryology in general.