272 



DIGESTIVE SYSTEM. 



entirely. Thus Wingradoff has shown that frogs, in which 

 this disease has been produced, recover if put in a cold 

 place, a low temperature serving to check fermentation ; but 

 the disease reappears if the animal be replaced in an atmos- 

 phere sufficiently warm to allow of fermentation taking place. 1 

 The most remarkable case, however, of diabetes artificially 

 produced is that in which it is caused by special modifications 

 wrought in the nervous system. Cl. Bernard discovered that 

 if a puncture be made in the floor (in P', Fig. 71) of the fourth 

 ventricle, of an animal (a rabbit), between the roots of the 



auditory and those of the 

 pneumogastric nerves, sugar 

 is found a short time after- 

 wards (an hour and some- 

 times less) in the urine of the 

 animal. (A puncture made 

 a little higher up, as at P, 

 produces glycosuria, accom- 

 panied by polyuria ; a little 

 higher up, the puncture pro- 

 duces ulbummuria.) This 

 glycosuria is caused by the 

 hepatic function, Wingra- 

 doff having shown that if 

 the fourth ventricle of a 

 frog be pricked, thus pro- 

 ducing diabetes, the disease will disappear if the liver, which 

 is the sugar-producing organ, be removed. We know, on 

 the other hand, that after a long course of slow poisoning by 

 arsenic the liver loses its glycogenous matter and thus the 

 power of producing sugar; and, in this case, a puncture in 

 the fourth ventricle of an animal does not produce diabetes. 

 The nerve-tract which unites the fourth ventricle to the 

 liver appears to belong, not to the pneumogastric, but to the 

 great sympathetic nerve, as was imagined by Cl. Bernard, 

 and directly proved by Schiff and Moos : the latter, espe- 



1 See Cl. Bernard, " Cours du College de France." (In Revue 

 des Cours Scientifiques, avril, 1873.) 



* The lobes of the cerebellum are separated : below are seen the restif orm 

 bodies whose divergence surrounds the point of the calamus scriptorius and the 

 fourth ventricle. The puncture P', which produces ylycosmia, is situated a little 

 above the point of the calamus. The puncture P is made at the level of the 

 tubercles of Wenzel ; that is to say, the origin of the auditory nerves. (CL Ber- 

 nard.) 



Pig. 71. Fourth ventricle (rabbit) and 

 experimental punctures.* 



