A recent tendency in descriptive neurology / by George L. Streeter.

  • Streeter, George Linius, 1873-1948.
Date:
[1907]
Catalogue details

Licence: In copyright

Credit: A recent tendency in descriptive neurology / by George L. Streeter. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    6/10 (page 12)
    units, however, differ from those of Meyer in being made in a longi- tudinal direction, while those of the latter consist as we have seen of transverse segments. There are, according to Johnston, two main activities in the vertebrate organism: first, actions in relation to external world (somatic), and secondly, internal activities having to do with processes of nutrition and reproduction (visceral). In each case there is a two-fold activity on the part of the nervous system; reception of stimuli and motor responses. Thus the nervous system consists of four functional divisions: Somatic sensory elements. Somatic motor elements. Visceral sensory elements. Visceral motor elements. Fig. 2. Profile and two transverse sections of a simple vertebrate brain, showing arrangement of the four primary divisions of the nervous system. After Johnston. With certain exceptions each of these divisions is represented in each segment of the nervous system, and all of the segments of a given divi- sion are serially homologous. Structurally and functionally they con- stitute bilaterally four longitudinal columns, which, according to him, are the primary elements of the nervous system and are more funda- mental than the metamerism of the body. The arrangement of these divisions is shown in Fig. 2, which is taken from Johnston’s book. In addition to the four primary divisions there are the group of brain centers and tracts which perform functions of correlation and also the specialized sympathetic system. Under these headings then he classi- fies the whole nervous mechanism. The method of treatment adopted