THE PANCREAS AND DIABETES 071 



to 6.25 grams protein, and if for oucli 0.25 Krarus i)r()t<'iii iiiotabolized 

 as indicated by the N in the urine, 3.65 grams glucose are excreted, then 

 58 per cent, of the protein motaboiized is converted into ghicose and 

 so excreted. In like manner the 2.S : 1 ratio would indicate a 45 

 jier cent, conversion. A perccMitaKc above 58 has not bo('nsat.isfactf)rily 

 proved to occur. If to the fully phlorhizinized dog a definite quantity 

 of glucose, galactose, starch or other assimilable form of carbohydrate 

 is given, this may under favorable circumstances be excreted quanti- 

 tatively in the urine as glucose, and the ratio of G : N will rise. The 

 sugar which appears in the urine under such circumstances over 

 and above that represented by N X G : N has been called "extra 

 sugar" by Lusk. 



If all the carbon contained in protein were converted into glucose, 

 and all this excreted together with the nitrogen, the G : N ratio would 

 be 8.25: 1. A higher ratio than this would necessarily mean that 

 sugar was coming from some source other than protein, or that all 

 of the N was not appearing in the urine, some being retained in the 

 body. If the liver were free from glycogen and no carbohydrate 

 were eaten, such a high ratio would speak in favor of sugar formation 

 from fat. Falta reports having seen cases of diabetes in which this 

 occurred, but in human cases it is difficult to be sure of the absence of 

 glycogen and food carbohydrate; moreover, such high ratios, unless 

 too long continued, might imply retention of nitrogen. 



Sugar from other Substances. — A large number of other substances 

 when administered to phlorhizinized dogs are capable of increasing 

 the output of sugar. Of importance in this connection are certain of 

 the amino acids, viz; glj^cine, alanine, aspartic and glutamic acids, 

 and arginine. Others, such as leucine, tyrosine and phenyl alanine 

 do not form sugar in the bod}^ but increase the output of the acetone 

 substances. The sugar-forming power of protein is doubtless due to 

 its content of the former group of amino acids."*- Lactic a.cid and gly- 

 cerol are also among the sugar formers. 



The chief interest in phlorhizin diabetes lies in the opportunities 

 it offers of studying the character of the intermediate metabolism 

 minus that of sugar, and so of studying sugar metabolism. Another 

 interest might be found were the physiologic effects of this glucoside 

 in animals interpreted with relationship to its normal role in plant 

 physiology. 



PANCREAS, DIABETES AND DIABETES MELITUS 



Historical. — In 1788 Cawley reported atrophy and stone of the 

 pancreas in a case of diabetes. The coincidence of diabetic symp- 

 toms and lesions of the pancreas was further studied by Bright, Lloyd 

 and Elliotson (1833). It was Bouchardat" who first definitely for- 



■•2 See Dakin, Jour. Biol. Chem.. 1913 (14), 155. 



" "De la Glycosurie, etc.," II edit., Paris, 1883. Cited from Naunyn. 



