The principles of psychology . s from the past, are almost sure tobe more or less biassed thereby. While intending to avoidassumptions they are in great danger of having their con-clusions vitiated, if not by some ancient or medireval ideaunder its overt form, yet by corollaries from it that haveunobtrusively embodied themselves in unsuspected pos-tulates. As we shall presently see, even physiologists havebeen in some cases thus misled. Hence, then, without at all calling in question the truthof those other and quite different interpretations of nervousphenomena that are tacitly expressed, in
The principles of psychology . s from the past, are almost sure tobe more or less biassed thereby. While intending to avoidassumptions they are in great danger of having their con-clusions vitiated, if not by some ancient or medireval ideaunder its overt form, yet by corollaries from it that haveunobtrusively embodied themselves in unsuspected pos-tulates. As we shall presently see, even physiologists havebeen in some cases thus misled. Hence, then, without at all calling in question the truthof those other and quite different interpretations of nervousphenomena that are tacitly expressed, in ordinary language,it is proper for us here to ignore them. Before studyingthe facts from a psychological point of view, we have first tostudy them from a physiological point of view. The pri-mary truth disclosed by the facts as so studied, is theuniversality of this relation between the degree of nervousevolution and the quantity and heterogeneity of the pro-duced motion. We now pass to the secondary truthssimilarly CHAPTER II. THE STRUCTURE OF THE NERVOUS STSTElf. § 8. An outline of nervous structure must precede adetailed account of it; and tlie essential facts to be indi-cated in an outline may be brouglit most clearly into view bycomparing with, one anotlier the nervous systems possessedby different types, and by different grades of the same will limit our comparisons to the thi-ee superior sub-kingdoms of animals. A minute nodule with diverging threads constitutes therudimentary nervous system, as existing in the lowestMollusk. In the Lamellibranchs several such minutenodules, or ganglia, are distributed, usually in pairs, indifferent parts of the body; and beyond th§ free fibreswhich they severally give off to neighbouring organs, thereare fibres by which they are connected together. Gastero-pods, considerably higher in organization and activity, havenervous centres among which a considerable heterogeneityis produced by the greater size of some than
Size: 2010px × 1243px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1860, bookidpri, booksubjectpsychology
