VitalismandOrganizedMechanisms

VitalismandOrganizedMechanisms - Vitalism and Organized...

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1 Vitalism and Organized Mechanisms Albrecht von Haller (1708-1777): A prototypical mechanist Solid parts of bodies are fibrous, composed of particles held together in linear strands by gluten or jelly – Particles contain air, chalk, and iron • lost by mechanical abrasions or friction – Gluten contains air, oil, water, and volatile salts • lost by breathing, sweat, urine, tears and secretions Nutrition restored both the particles and the gluten Living things exhibit sensibility and irritability – Only nerve exhibits sensibility – Only muscle exhibit irritability – Von Haller attributed these properties to the gluten John Hunter (1728-1793): A vitalist retort Ordinary matter is transformed into vegetable or animal matter, but l No chemist on earth can make out of the earth a piece of sugar, but a vegetable can do it. z So, there is something special about living things that sets them apart – For Hunter this is the fact that they can only be made by living things Hunter’s claim gives context to Wöhler ` s excitement after synthesizing urea—chemists could, it seemed, make organic compounds
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2 Marie François Xavier Bichat (1771-1802) l Life consists in the sum of the functions, by which death is resisted z l The measure, then, of life in general, is the difference which exists between the effort of exterior power, and that of interior resistance. z – What is meant by saying life is resisting death? l As Newton ascribed basic 'properties' (for example gravitation) to the physical matter of the cosmos, physicians should ascribe 'properties' to the physiological matter of life. But vital properties should be clearly distinguished from physical ones. Let us leave to chemistry its affinity, to physics its elasticity and gravity, and let us employ in physiology only sensibility and contractility . z Bichat Allows Mechanistic Decomposition Down to Tissues l Chemistry has its simple bodies, which form, by the combinations of which they are susceptible, the compound bodies; such are coloric, light, hydrogen, oxygen, carbon, azote [nitrogen], phosphorus, &c. In the same way anatomy has its simple textures, which, by their combinations four with four, six with six, eight with eight, &c., make the organs. These textures are, 1 st . the cellular; 2d. the nervous of animal life; 3d. the nervous of organic life; 4 th . the arterial . . . These are the true organized elements of our bodies. Their nature is constantly the same, everywhere they are met with. z Anatomie g é n é rale Bichat: Tissues as Source of Vital Properties l Shall I speak of the vital properties? See the animal sensibility predominant in the nerves, contractility of the same kind particularly marked in the voluntary muscles, sensible organic contractility, forming the peculiar property of the involuntary, insensible contractility and sensibility of the same nature, which is not separated from it more than from the preceding, charactering
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VitalismandOrganizedMechanisms - Vitalism and Organized...

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