314 THE EQUILIBRIUM OF COLLOID AND 



This experiment would appear to demonstrate that the sugar 

 in the serum exists in some form of feeble union with the protein 

 which the action of the mild acidity of the carbon dioxide or the 

 residual affinity of the anaesthetic is sufficient to break up, so leaving 

 the sugar free to dialyse out. 



This union of carbohydrate and protein throws a light on the 

 glycosuria which follows hyperglycaemia. For in hyperglycaemia 

 there is an excess of sugar above that which can enter into union 

 with the protein, and it is this excess which is seized upon and 

 thrown out into the urine by the kidney cells. From this point 

 of view it is interesting to note that in the living animal, when 

 there is more than a certain percentage of carbon dioxide in the 

 respired air for a given period, even though there be in the air 

 breathed more than the atmospheric proportion of oxygen, then 

 there invariably appears sugar in the urine in very considerable 

 amount. Also in the case of prolonged anaesthesia, especially if 

 the concentration of the anaesthetic administered be increased to 

 the maximum limit, there always appears sugar in the urine, often 

 in high percentages. The author has found as much as 11 per 

 cent, of sugar in the urine of dogs after ether anaesthesia, and has 

 shown that the reducing material present is undoubtedly glucose 

 by obtaining and separating typical glucosazone crystals in 

 abundance. 



In the liver cells there is undoubtedly union between the bio- 

 plasm and the sugar before glycogen is formed. The glycogen 

 up to a certain maximum limit at which it separates as granules 

 can also exist in union in the cell, for considerable amounts of 

 glycogen can be separated from the tissues long before separated 

 glycogen can be shown by histochemical methods. 



Similar evidence has been obtained by different authors as to 

 the formation of unions between cell proteins and fats. By certain 

 procedures, such as partial interference with blood- supply (Bain- 

 bridge and Leathes), it has been possible to make the cells of certain 

 organs, notably those of the liver, take on the appearances of fatty 

 degeneration. The cells become loaded with obvious fat globules, 

 which stain with all the usual histochemical staining reagents for 

 fatty substances. It looks at first sight as if the amount of fat in the 

 organ had been enormously increased, but the interesting point is 

 that comparative analyses of normal liver with no appearance of 

 fat in the cells, and of such liver cells apparently loaded up with 



