[Footnote 1: The diabetic area, as marked out by Eckhard, and which corresponds with the vaso-motor area, as defined by Owsjannikow (_Ludwig's Arbeiten_, 1871, p. 21), is bounded by a line drawn four or five mm. above the nib of the calamus scriptorius, and another about four mm. higher up.]
It was also learned in the course of continued experiment that glycosuria resulted upon transverse section of the medulla oblongata, of the spinal cord above the second dorsal vertebra, of the filaments of the sympathetic accompanying the vertebral artery, upon destruction or extirpation of the superior cervical ganglion, and sometimes, but not always, after division of the sympathetic in the chest (Pavy); also after section or careful extirpation of the last cervical ganglion, section of the two nerve-filaments passing from the lower cervical to the upper thoracic ganglion around the subclavian artery, forming thus the annulus of Vieussens,[2] and after section or removal of the upper thoracic ganglion.
[Footnote 2: Cyon and Aladoff, reprint from the _Mélanges biolgiques_ and _Bullétin de l'Académie Impériale de Petersbourg_, vol. xiii. p. 91; cited by Dr. Brunton in the Lectures named in note on p. 198; also _British Medical Journal_, Dec. 23, 1871, p. 731.]
[Illustration: FIG. 2. The last cervical and first thoracic ganglia, with circle of Vieussens, in the rabbit, left side. (Somewhat diagrammatic, many of the various branches being omitted.)
_Trach._, trachea; _Ca._, carotid artery; _n. vag._, the vagus trunk; _n. rec._, the recurrent laryngeal; _sym._, the cervical sympathetic nerve ending in the inferior cervical ganglia, _gl. cerv. inf._ Two roots of the ganglion are shown--_rad._, the lower of the two accompanying the vertebral artery, _A. vert._, and being the one generally possessing accelerator properties; _gl. thor. pr._, the first thoracic ganglion. Its two branches, communicating with the cervical ganglion, surround the subclavian artery, forming the annulus of Vieussens. _sym. thor._, the thoracic sympathetic chain; _n. dep._, depressor nerve. This is joined in its course by a branch from the lower cervical ganglion, there being a small ganglion at their junction, from which proceed nerves to form a plexus over the arch of the aorta. It is this branch from the lower cervical ganglion which possesses accelerator properties, hence the course of the accelerator fibre is indicated in the figure by the arrows. (Modified from Foster's _Physiology_.)]