. First lessons in zoology. Zoology. FOOD /IND /41R TURNED INTO FLESH /iND ENERGY 89 ering the production of energy and making of body mate- rial we saw that the same substances provided for both. In fact whatever the form of food, animal, or plant, the elementary substances are the same, being conveniently classified into two great groups, organic and inorganic substances. Inorganic food substances are water and certain minerals of which common salt is one. Organic food substances are of three kinds or groups. The first group, called the. Fig. 52. -Mouth, with prehensile under lip, of young d
. First lessons in zoology. Zoology. FOOD /IND /41R TURNED INTO FLESH /iND ENERGY 89 ering the production of energy and making of body mate- rial we saw that the same substances provided for both. In fact whatever the form of food, animal, or plant, the elementary substances are the same, being conveniently classified into two great groups, organic and inorganic substances. Inorganic food substances are water and certain minerals of which common salt is one. Organic food substances are of three kinds or groups. The first group, called the. Fig. 52. -Mouth, with prehensile under lip, of young dragon-fly. Jenkins and Kellogg.) (From proteids, of which the white of egg is an example, forms a large part of the tissues of animals; the second group is made up of the fats and oils; the third, known as the carbohydrates, consists of the starches and sugars. Now digestion consists in changing all these substances into soluble form so that they can be absorbed into the body, circulate with the blood, if there be any, and then pass into the living cells for their use. This change is accomplished by certain liquids called digestive fluids. The digestive apparatus varies like other parts of the ani- mal organism, being most simple in some forms and very complex in others. In Amoeba the food particles are retained in spaces in the cell until they are digested. So in other Protozoa. The simple digestive cavity of the hydra has been referred to (fig. 54). In the polyps and jelly-fishes (see Chapter X), this cavity is extended, the digestive surface being much increased by partitions,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Kellogg, Vernon L. (Vernon Lyman), 1867-1937. New York, H. Holt and Company
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1903
