210 FUNCTIONS OP NUTRITION. 



a condition of diabetes. Yon Becker* found that in rabbits, if glucose 

 be present in the blood in the proportion of 5 parts per thousand, it 

 passes off by the urine, where it may be recognized by the copper test ; 

 but if less abundant than this, its indications in the urine are faint and 

 uncertain. Bernard, f by injecting a solution of glucose into the veins 

 of the rabbit, generally produced a condition of diabetes when the glu- 

 cose was injected in larger quantity than one part per thousand of the 

 bodily weight. The effect of such injections is, however, temporary, 

 passing off when the surplus of saccharine matter has been expelled 

 from the system. According to Yon Becker, a solution of glucose, 

 injected into the jugular vein of the rabbit in sufficient quantity, may 

 cause the appearance of sugar in the urine in less than three hours; 

 but at the end of six or seven hours the whole of it may be eliminated, 

 so that it is no longer found in the excretions. 



A variety of circumstances may so increase the proportion of glucose 

 in the blood as to cause a saccharine condition of the urine. 



I. One of these causes is an unusually abundant and rapid absorp- 

 tion of sugar from the intestine. Where a very large quantity of 

 sugar is suddenly absorbed, and at once carried by the portal vein to 

 the liver, this organ is not capable of immediately converting the whole 

 of it into glycogen. A portion thus passes the hepatic circulation un- 

 changed, and, reaching the general circulation in unusual quantity, is 

 discharged with the urine. Yon Becker observed that when concen- 

 trated solutions of glucose are introduced in abundance into the intes- 

 tine of the rabbit, it may subsequently appear in the urine. Bernard 

 also found that if in the rabbit, after one or two days' fasting, sugar in 

 large amount be injected into the stomach, the urine becomes diabetic ; 

 and he observed the same thing in the human subject, in consequence 

 of taking a large quantity of sugar in solution when the stomach had 

 been empty for several hours. This result is produced only when a 

 much greater abundance of sugar is present in the intestine than in 

 ordinary digestion, and depends on the excessive quantity absorbed in 

 a short time. 



II. A diabetic condition may also be induced by anything which 

 hastens the circulation through the liver, or increases its supply of 

 blood. Many observers have met with this result from a variety of 

 causes. Bernard found that in dogs the venous blood may present 

 traces of glucose after the abdomen has been subjected to pressure or 

 manipulation over the region of the liver, and after continued struggles 

 or convulsive action, by which the abdominal organs are forcibly com- 

 pressed. In the same animal, according to Harley, the injection of 

 weak solutions of ammonia or ether into the portal vein may be followed 

 by a saccharine condition of the urine. It has also been observed in 

 man, after a bruise in the right hypochondriac region. The resistance 



* Zeitschrift fur wissenschaftliche Zoologie, Band v., p. 176. 



f Leyons sur les Liquides de 1'Organisme. Paris, 1859, tome ii., p. 73. 



