Text-book of human physiology : including histology and microscopical anatomy with especial reference to the practice of medicine / by L. Landois.

Leonard Landois

Date:: [1904]

Credit: Text-book of human physiology : including histology and microscopical anatomy with especial reference to the practice of medicine / by L. Landois. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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$15 MATTER. If it be desired to give a special position in the system of organisms to those beings that occupy the lowest ]:)lane of development and that, representing to a cer- tain degree the prototype in the family history, ha\e as yet not been differentiated into animal and vegetable, the so-called protists (Haeckel), these likewise wovild occupy a distinct place in the foregoing arrangement by the side of animals and plants. Morphology and physiology are coordinate branches of biology. A knowledge of morphology is a prerequisite for the comprehension of physiology, inasmuch as the functions of an organ can be correctly understood only if its external form and its internal structure are pre- viously known. The developmental history occupies an intermediate position between morphology and physiolog^^ It is a department of morphology in so far as it has to do with a description of the parts of the developing organism; it is a physiologic study in so far as it investi- gates the functions and vital phenomena during the period of develop- ment of the organism. In all the branches of biologic science it is neces- sary to enter upon a consideration of physical and chemical principles. MATTER. The entire visible world, including all organisms, consists of matter, that is, of the material or substance that occupies space. A distinction is made between ponderable matter (in ordinary language often desig- nated simply matter), w^hicli can be weighed upon the scales; and im- ponderable matter, which cannot be weighed upon the scales. The latter is designated ether (also luminiferous ether or light-ether). Ponderable matter or bodies possess jorui (or shape), that is, the outline of their limit- ing surfaces; also volnnie, that is, the amount of space they occupy; and finally an aggregate condition, which takes a solid, liquid, or gaseous form. The ether fills the space of the universe, at any rate, with certainty to the most remote visible stars. This light-ether, notwithstanding it's imponderability, possesses quite definite mechanical properties. It is infinitely more attenuated than any other knowm form of gas, and never- theless its behavior corresponds rather with that of a solid body than with that of a gas. It more nearly resembles a gelatinous mass than air. It takes part in the vibrations of the atoms of the most distant stars associated with the luminous phenomena of the latter, and it is thus the carrier of light, which through its vibrations it conducts to the visual apparatus with inconceivable rapidity (300,000 kilometers in the second). Imponderable matter (ether) and ponderable matter (substance) are not sharply delimited from each other; on the contrary, the ether pene- trates the interstices present in the smallest particles of ponderable matter. If ponderable matter be conceived to be divided into gradually smaller and sinaller parts, in the process of progressive subdivision parts would eventually be reached whose aggregate condition would still be recognizable. These are designated particles. Particles of iron would still be recognized as solid, those of water as fluid, and those of oxygen as gaseous. If it be conceived that the process of division of the parti- cles be carried to a further degree, a point will finally be reached beyond which further division cannot be effected either by mechanical or by physical means. In this way the molecule is obtained. A molecule,$