Organs, essential vegetative

Yellow ochres are earths composed essentially of clay coloured by hydrated ferric oxide they may contain siliceous sand, calcium carbonate, small proportions of manganese oxides, and sometimes basic ferric sulphate and calcium and barium sulphates. Chalk, gypsum and heavy spar may be added fraudulently and the colour may be " improved by artificial organic dyes, vegetable colours or chrome yellow. 

Exempt colorants are made up of a wide variety of organic and inorganic compounds representing the animal, vegetable, and mineral kingdoms. Some, like -carotene and 2inc oxide, are essentially pure factory-produced chemicals of definite and known composition. Others, including annatto extract, cochineal extract, caramel, and beet powder are mixtures obtained from natural sources and have somewhat indefinite compositions. 

Many organic liquids, including oils (essential, animal, vegetable or mineral), alcohols, fatty acids, chlorinated hydrocarbons and aliphatic esters, are without action. The absence of any catalytic action of tin on oxidative changes is helpful in this respect. When, however, mineral acidity can arise, as with the chlorinated hydrocarbons containing water, there may be some corrosion, especially at elevated temperature. 

Biosynthesis of Unsaturated Fatty Acids. In the mammalian tissues, the forma-tion of monoene fatty acids is only possible. Oleic acid is derived from stearic acid, and palmitooleic acid, from palmitic acid. This synthesis is carried out in the endoplasmic reticulum of the liver cells via the monooxigenase oxidation chain. Any other unsaturated fatty acids are not produced in the human organism and must be supplied in vegetable food (plants are capable of generating polyene fatty acids). Polyene fatty acids are essential food factors for mammals. 

Oily fishmeal is allowed in organic rations and it has an even higher essential amino acid content than full-fat soya. However, its use in poultry rations is limited partly by cost, restrictions on the source of the fishmeal imposed by organic standards, the fact that some customers demand birds that are fed on a vegetable-based diet and concerns about fishy taints to the product (Walker and Gordon, 2001). 

Two groups of chemical elements can be considered related to their distribution in soil profiles. The first group includes the essential nutrients actively absorbed by vegetation and relatively tightly bound in soil organic matter (Figure 11). 

Herman Boerhaave was a professor of the medical school of Leiden whose chemical textbook became a very important contributor to the early eighteenth-century organization of chemistry, as will be seen in the next chapter. But he seems to have vacillated on the role of air as a chemical component of bodies. Initially he considered air in essentially the same way as Boyle, a chaos of various smokes and effluvia which accounted for its particular chemical actions, but whose elastic parts were entirely without chemical behavior. After the appearance of Vegetable Staticks, however, he seems to have accepted Hales evidence without really abandoning his earlier view. When Lavoisier in 1774 summarized the earlier literature on the chemical fixing and liberation of air, he wrote of Boerhaaves views thus ... 

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