56 Dr. F. W. Pavy on the Production of Glycosuria. [Nov. 25, 



atmospheric air, would be the same, as far as the urine is concerned, as 

 that of carbonic oxide. On account of the facility with which the 

 abstraction of oxygen is effected, we obtain our escape from being glyco- 

 suric under the process of oxygen inhalation naturally carried on. The 

 capacity of abstraction, however, is not unlimited, and, as has been shown 

 in this communication, glycosuria may be induced by artificially surcharg- 

 ing the blood with inhaled oxygen. 



As yet I have only assumed, without adducing any experimental 

 evidence upon the point, that the production of glycosuria by the inhala- 

 tion of carbonic oxide is due to the direct action of the blood impregnated 

 with the gas upon the liver. It might be urged that the effect is attribu- 

 table to hyperemia of the liver, the hyperemia being brought about either 

 through the state of the arteries of the organ, or that of the chylo-poietic 

 vessels in general leading to increased pressure in the portal system. 

 An appeal to experiment has afforded a decided answer to these sugges- 

 tions. 



In the first place I ligatured the hepatic artery of an animal while 

 under the effects of chloroform, and afterwards subjected it to the 

 influence of puff-ball smoke. Before exposure to the inhalation of the 

 puff-ball smoke, the urine was ascertained to be free from sugar. Twenty 

 minutes after the cessation of the inhalation the urine contained 11 5 

 grains of sugar to the fluid ounce. The hepatic artery being tied, direct 

 arterial hyperaeniia of the liver was out of the question as a cause 

 of the glycosuria. 



In the next place I directed my attention to the question of the possi- 

 bility of the effect being due to hypersemia of the liver occurring as a 

 result of an increased activity of the circulation through th'e chylo- 

 poietic viscera, and thence an increased flow of blood through the portal 

 vein. It was difficult certainly to realize that any thing like the hypersemic 

 state producible through the arterial system could be induced through 

 the medium of the portal vein, looking at the position of the vessel with 

 its delicate walled radicles and a capillary circulation behind. But how- 

 ever this might be, I determined to submit the point to experimental 

 inquiry. 



If hypersemia of the liver from an increased afflux of portal blood con- 

 stituted the cause of the glycosuria, it ought to be averted on cutting off 

 a considerable portion of the flow through the chylo-poietic viscera. 



In one experiment to accomplish this I tied the superior mesenteric 

 artery of a dog, while the animal was under the influence of chloroform, 

 and half an hour afterwards caused it to inhale a mixture of carbonic 

 oxide and air, in the proportion of one part of the former to nineteen of 

 the latter. Notwithstanding this extent of dilution it was found neces- 

 sary to allow the animal to breathe pure air from time to time, to prevent 

 a fatal result occurring. The inhalation was carried on in the manner 

 stated for half an hour. Some urine was collected at the commencement, 



