[Footnote 3: _Beiträge zur Anat. und Physiologie_, iv., 1859, p. 1; vii., 1873.]
In view of the fact that Eckhard[4] has failed to confirm the results of Cyon and Aladoff, but has traced the glycogenic influence down the spinal cord as far as the fourth dorsal vertebra in rabbits, and even a little lower, and that Schiff[5] has shown that diabetes sometimes results after section of the anterior columns of the cord between the medulla and the fourth cervical vertebra, Dr. Brunton[6] suggests that the vaso-motor nerves of the liver may not always leave the spinal cord to join the sympathetic by the branches accompanying the vertebral artery, but sometimes pass farther down the cord, leaving it by the communicating branches to some of the dorsal ganglia, as indicated in Fig. 4.
[Footnote 4: _Beiträge zur Anat. u. Physiologie_, viii., 1877, p. 79.]
[Footnote 5: _Untersuchungen über Zuckerbildung in der Leber_, 1859, S. 108.]
[Footnote 6: _Lectures on the Pathology and Treatment of Diabetes Mellitus_; reprinted from the _British Medical Journal_, 1874, p. 12.]
[Illustration: FIG. 4. Diagram showing another course which the vaso-motor nerves of the liver may take. The letters indicate the same parts as in Fig. 3. The hepatic vaso-motor nerves are here represented as passing lower down the cord than in Fig. 3, and leaving it by communicating branches to the second dorsal ganglion. It is possible that they may sometimes leave by the branches to the first, and sometimes by those going to a lower, ganglion. In such cases any irritation to the third or one of the other cervical ganglia may cause diabetes by being conveyed along the vertebral artery and up the cord, as indicated by the dark line, to the vaso-motor centre, where it may cause reflex inhibition in the same way as any irritation to the vagus.]
It is evident that an agency involving any part of this tract in such a way as to paralyze the vaso-motor nerves of the liver is capable of producing glycosuria. Such cause may operate upon the central ganglia whence the nerves emanate, as the vicinity of the oblongata and upper parts of the spinal cord or the coeliac ganglion and its branches, including those to the pancreas. Or the irritation may be peripheral and its effects reflex. We have seen that irritation of the central end of the cut vagus will produce glycosuria. Any irritation, therefore, involving the peripheral distribution of this nerve may produce it. Hence embarrassed respiration, whether due to disease of the respiratory passages, strangulation, or inhalation of irrespirable gases and anæsthetics, produces glycosuria in dogs and rabbits; and this symptom has been known to attend these conditions in the human subject. So, too, glycosuria may be produced by such substances as woorara, strychnia, morphia, and phosphoric acid, introduced into the blood and irritating the terminal filaments of the pneumogastrics, or it may be brought about secondarily through the embarrassed respiration these drugs produce. Such peripheral { 199} irritation may reside also in the stomach, intestines, liver, or any organ to which the pneumogastric is distributed.