Volume 1

The book of nature study / edited by J. Bretland Farmer ; assisted by a staff of specialists.

Date:
[1908?]-1909
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: The book of nature study / edited by J. Bretland Farmer ; assisted by a staff of specialists. Source: Wellcome Collection.

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    process of building up and breaking down, of construction and destruction, and that ferments play a very important part. [If there is sufficient knowledge of chemistry, arrange a series of carbon compounds, from relatively simple ones to the height of complexity in proteids. Thus the formula of egg albumin is often stated as C201H322N52Oe6S2. Compare the body with a manufactory, noting the raw materials, their early transforma- tions, the finished products, and the waste products. But we have very little knowledge as yet of the “ secret room ” in the manufactory where the gist of the business is hidden.] Summary.—Although no one is wise enough to tell completely what is meant by the simple word alive, it is safe to say that active life involves the following facts—(a) The living organism has the power of growth at the expense of material different from itself. (b) The living organism has usually the power of reproducing other organisms like itself, (c) The living organism is subject to ceaseless chemical change, in which the complex substances known as proteids are essentially involved, and yet it has the power of persistence, of remaining more or less the same for prolonged periods. (d) The living organism gives effective responses to external stimuli; it has a power of control and self- regulation, it has a unified behaviour. Section 2.—The Everyday Activities of Animals.—There is a contrast between everyday activities, which are always going on, and the periodic activities of growing and reproducing. The everyday activities or functions of the animal body are five. There are the two “ master-activities ” of contractility and of irritability, of the muscular and of the nervous systems respectively, of moving and feeling in the wide sense. These make life worth living. On a different plane are the three “ auxiliary ” or “ sustentative functions ” which keep the two master-activities agoing. These are nutrition, including the ingestion, digestion, and final incorporation or absorption of food ; respiration, in- cluding the absorption of oxygen (really a gaseous food) to keep the vital combustion agoing, and the elimination of carbon dioxide (really a gaseous waste) ; and excretion, the filtering out of the nitrogenous waste,—part of the ashes of the living fire.