488 OF SECRETION AND EXCRETION. 



the liver, such section ought to be always followed by glycosuria, but this is 

 by no means the case, and a rational explanation of its non-occurrence has 

 been given by Cyon and Aladoff to the effect that although the section does 

 really produce vaso-motor paralysis of the vessels of the liver, yet that the 

 current of blood is not materially increased in vigor, because the same sec- 

 tion, if made high up, coincidentally paralyzes the vessels of the abdominal 

 viscera, which, owing to their great size, imprison as it were a large quantity 

 of the blood. The reflex influence of the pneumogastric nerves on the liver 

 is shown by dividing it and irritating the upper cut surface ; sugar then 

 appears in the urine in consequence of the paralysis of the vaso-motor centre. 

 Irritation of the lower cut surface is without effect. The pneumogastrics are 

 therefore the sensory nerves of the liver. It may here be remarked that the 

 close relationship of the secretion of bile with the formation of glycogen is 

 demonstrated by the observations of Dr. Legg, 1 who has shown that after 

 ligature or complete obstruction of the Hepatic ducts, glycogen is no longer 

 formed by the Liver, and that puncture of the fourth ventricle fails to pro- 

 duce diabetes. 



400. The influence of medicinal agents upon the glycogenic function of the 

 Liver has received but little attention, though various substances are known 

 to be capable of inducing diabetes. Coze" found the proportion of sugar 

 nearly double both in the liver and in arterial blood after the administration 

 of morphia. Pavy 3 observed well-marked diabetes in animals after the ad- 

 ministration of phosphoric acid, and also after poisonous doses of strychnia, 

 when the circulation was maintained by artificial respiration. Harley ob- 

 tained the same result in himself after eating freely of asparagus. Certain 

 poisons, as woorara (Schiff), produce it, as well as very vigorous artificial 

 respiration. Ewald 4 observed it in Rabbits after the subcutaneous injection 

 of nitro-benzole. The administration of large doses of caustic potash, or of 

 carbonate of soda, is stated by Dr. Pavy to prevent the occurrence of diabetes 

 under circumstances in which it would otherwise have been induced. Dia- 

 betes may be produced by disturbances of the respiratory processes. Thus 

 it occurs in Asphyxia, as in poisoning with carbonic oxide gas (Schiff), and 

 Harley observed it in animals under the influence of ether, chloroform, 

 liquor ammonite, and methylated spirit. 5 Reynoso 6 produced it by making 

 animals respire the vapors of benzoin and acetoin, and found that it followed 

 asphyxia slowly produced by the inhalation of carbonic, hydrocyanic, and 

 sulphuretted hydrogen gases. Diabetes may also be produced by disturbances 

 in the circulation. Thus Schiff found that retention of the blood or retarda- 

 tion of the blood-current in any part, such as ligature or compression of the 

 larger vessels, will lead to its occurrence. Tieffenbach, however, found that 

 the amount of sugar was increased by arrest of the circulation through the 

 aorta or vena portre. An experiment made by Winogradoff shows conclu- 

 sively that the Sugar is formed directly or indirectly by the liver, for when 

 diabetes has been produced by puncture of the floor of the fourth ventricle 

 it at once ceases on ablation of the liver, and a similar conclusion may be 

 arrived at by puncturing the fourth ventricle in an animal to which arsenic 

 has been administered for some time, for this drug has been found to prevent 

 the formation of glycogeu in the liver, and in consequence of the absence of 

 glycogen in the liver, sugar is not produced in sufficient quantity to lead to 

 its elimination by the kidneys. 



1 JiritMi Med. Journal, 1874, p. 646, vol. i, and Archiv f. Experiment Patholo- 

 gic, Bd. ii, II (-ft 5. 



2 Comptcs Kcndus, 1857. 3 Proceedings of the Royal Society, No. 35. 

 4 Ontralblatt, 1878, p. 819. 5 See Proceed, of Hoy. S'oc., 1860. 



6 Annal. d. Sci. .Nat., 1855, p. 131. 



