FUNCTION OF THE LIVER. 115 



After its production in the liver, grape sugar passes into the circulation and dis- 

 appears in the lungs as long as a normal respiration is maintained. I demonstrated 

 by numerous careful 1 experiments upon cold-blooded animals the following facts: — 



1. Grape sugar is never normally a constituent of the urine. 



2. If the supply of oxygen be cut off from cold-blooded animals by placing them 

 in carbonic acid or hydrogen gas, or by closing the trachea completely, grape 

 sugar accumulates in the blood and is eliminated by the kidneys. The disappear- 

 ance of this substance in the lungs depends, therefore, upon the introduction of 

 oxygen. 



3. In cold-blooded animals the function of the liver in producing sugar continued 

 after the exclusion of the oxygen. 



4. The appearance of grape sugar in the urine was accompanied in every instance 

 by remarkable alterations in the forms and appearance of the blood-corpuscles under 

 the microscope. 



1 The excretions of the kidneys in cold-blooded animals, generally, are scanty. Chelonians are the 

 best adapted for such experiments on account of their capacious bladders. They were prepared by 

 being starved for a length of time, and then transferred to a tub of water and abundantly supplied with 

 vegetable food (Portulacca oleracea). The excretions of the kidneys were thus rendered copious. 



