464 SECRETION. 



idly that no sugar could be formed by the liver post mortem. These experiments leave 

 no doubt of the fact that, during life and in health, the blood, as it passes through the 

 liver and is discharged by the hepatic veins into the vena cava, contains sugar, which is 

 formed by the liver, independently of the sugar and starch taken as food. 



Does the Liver contain Sugar normally during Life? This is the only question upon 

 which the results of reliable experiments have been entirely opposite. Bernard made 

 the greater part of his observations by analyzing the substance of the liver; and he 

 arrived at most of his conclusions with regard to the variations in the glycogenic function, 

 from estimates of the proportion of sugar in the liver under different conditions. For 

 many years we have been in the habit of repeating these experiments, with like results, 

 and we have never failed to find sugar under normal conditions of the system. We were 

 formerly in the habit of making the demonstrations of the formation of sugar in the liver 

 upon animals that had been etherized ; and then we always obtained a brilliant precipitate 

 from the clear extract of the substance of the liver boiled with the test-liquid. The 

 experiment was performed in this way before we had acquired sufficient dexterity to seize 

 the portal vein readily and to go through with the necessary manipulations with rapidity. 

 We subsequently made the operation by first suddenly breaking up the medulla oblon- 

 gata, then making a small incision into the abdominal cavity, seizing the portal vein 

 instantly, and following out the remaining steps of the experiment without delay. In this 

 way, although sugar was always found in the blood of the hepatic veins, we frequently 

 failed to obtain a distinct reaction in the extract of the liver ; and it appeared, indeed, that 

 the more accurately and rapidly the operation was performed, the more difficult was it 

 to detect sugar in the hepatic substance. It seems probable, in reflecting upon these 

 facts, that, inasmuch as no one has assumed that the actual quantity of sugar produced 

 by the liver is very considerable, and as a large quantity of blood (in which the sugar 

 is very soluble) is constantly passing through the liver, precisely as we pass water through 

 its vessels to remove the sugar, the sugar might be washed out by the blood as fast 

 as it is formed ; and that really the liver might never contain sugar in its substance, as 

 a physiological condition, although it is constantly engaged in its production. We know 

 that the characteristic elements of the various secretions proper are produced in the 

 substance of the glands and are washed out at the proper time by liquid derived from 

 the blood, which circulates in their substance during their functional activity in very 

 much greater quantity than during the intervals of secretion. Now, the liver-sugar may 

 certainly be regarded as an element of secretion ; and, possibly, it may be completely 

 washed out of the liver, as fast as it is formed, by the current of blood, the hepatic 

 vein, in this regard, serving as an excretory duct. To put this hypothesis to the test 

 of experiment, it was necessary to obtain and analyze a specimen of the liver in a condi- 

 tion as near as possible to that under which it exists in the living organism ; and, in 

 carrying out this idea, we instituted the following experiments : 



Experiment I. A medium-sized dog, full-grown, in good condition, and not in digestion, 

 was held upon the operating-table by two assistants, and the abdomen was widely opened 

 by a single sweep of the knife. A portion of the liver, weighing about two ounces, was 

 then excised and immediately cut into small pieces, which were allowed to fall into boil- 

 ing water. The time from the first incision until the liver was in the boiling water was 

 twenty-eight seconds. An excess of crystallized sulphate of soda was then added, and 

 the mixture was boiled for about five minutes. It was then thrown upon a filter, and the 

 clear fluid that passed through was tested for sugar by Trommer's test. The reaction 

 was doubtful and afforded no marked evidence of sugar. 



Experiment II. A medium-sized dog, in the same condition as the animal in the first 

 experiment, was held upon the table, and a portion of the liver was excised, as above 



ments are the first on record, made with the view above indicated. The experiments by Dr. Lusk and by Dr. Dai- 

 ton were made later, with the view of confirming our original observations. 



