80 LECTURE V. 



salt l is introduced into the vascular system, glucosuria ensues. If, on 

 the other hand, the splanchnic nerves are severed, the salt infusion 

 becomes ineffective. Morphia 2 behaves similarly. Quite recently the 

 exact connection between these experiments and the glucosuria produced 

 by the " diabetic puncture " has been developed by Martin H. Fischer. 3 He 

 showed, first of all, that instead of the one-sixth-molar solution of common 

 salt which he injected into the circulatory system of rabbits at the rate of 

 75 to 100 c.c. per minute, one-sixth-molar solutions of other sodium salts 

 e.g., NaBr, Nal, NaNO 3 could be used with the same effect. 4 Fischer 

 showed, furthermore, that the cause of the glucosuria was not a per- 

 manent injury produced in any organ, for he could cure the disease 

 by the use of a solution of calcium chloride. A renewed injection of the 

 common salt would, however, again lead to glucosuria. The greater 

 the concentration of the solution of sodium salt employed, the sooner 

 the sugar appeared in the urine. 



Fischer, now, sought to determine upon which tissues the solution of 

 salt acted in producing this glucosuria. He remembered at the same time 

 the experiments of Kiilz, who observed that glucosuria was only produced 

 when the splanchnic nerves remained intact. Fischer found that after 

 cutting these nerves, he could not produce glucosuria, and, furthermore, 

 if the glucosuria was already established before the nerves were severed, it 

 would disappear shortly after the operation. This suggested the thought 

 that probably the salt solution produced some such action as that pro- 

 duced by the vagi nerves upon the sugar center. Fischer sought to localize 

 the action of the common salt as much as possible, For this purpose he 

 tied the axillary artery in some rabbits, and injected the solution of salt 

 into the central end of this artery so that the salt passed on through the 

 vertebral artery directly to the medulla oblongata. When the salt solu- 

 tion was injected in this way, the sugar appeared in the urine somewhat 

 more quickly than when the same amount of the same solution was intro- 

 duced into a peripheral vessel. Furthermore, the glucosuria was more 

 severe and was more lasting. As much as 7.3 per cent of urine sugar 

 was found in the urine. These experiments make it seem probable that 

 the salts introduced into the circulation act upon the same center as that 

 of the " diabetic puncture." 



There are other poisons known which will produce glucosuria, strychnine, 

 for example. The poisonous effect of this substance is not obtained, 

 however, if the spinal cord, with the exception of the upper portions, is- 

 extirpated. Since strychnine does not cause elimination of sugar in the 



1 C. Eckhard: Beit. Anat. Physiol. 8, 77 (1879). 



' Kiilz: Eckhard's Beitrage, 6, 177 (1872). 



1 University of California Publications, Physiology, 1, 77 (1903), and 1, 87 (1904). 



4 LiCl, KC1, and SrCl 2 , produced glucosuria; NH 4 C1 did not. 



