94 



LECTURE V. 



who found that the limited absorption of oxygen was a result of the dis- 

 turbed carbohydrate metabolism, rather than the cause of it. The absorp- 

 tion of oxygen depends upon the combustion taking place in the body. 

 Leo, 1 as well as Weintraud and Laves, 2 has finally shown that the amount 

 of absorbed oxygen is the same with healthy people that it is with those 

 suffering from diabetes of equal weight and condition of nourishment, and 

 finally that the apparent decrease in the elimination of carbonic acid is 

 caused by the faulty decomposition of carbohydrates. 



Of especial importance as regards the cause of the insufficient consump- 

 tion of the sugar formed in the organism are the experiments performed by 

 O. Baumgarten 3 under the direction of von Mering. Baumgarten, at von 

 Mering's suggestion, tried some feeding experiments upon diabetics, and 

 upon dogs with removed pancreas, employing substances which are re- 

 garded as decomposition or oxidation products of the sugars. It was 

 found that d-gluconic acid, d-saccharic acid, mucic acid, glucuronic acid, 

 glucosamine-hydrochloride, succinic acid, d-tartaric acid, salicylic alde- 

 hyde and vanillin, were consumed by diabetics just as readily as by 

 healthy individuals. The following summary illustrates the relation 

 between some of these products and d-glucose (also called dextrose, or 

 grape-sugar) : 



CHO 'COOH CHO COOH COOH 

 H C OH H C OH H C OH H C OH H C OH* 



HO C H HO C H HO C H HO C H HO C H 



I I I I I 

 H C OH H C OH H C- OH H C OH HO C H 



I I I I I 

 H C OH H C OH H C OH H C OH H C OH 



I I 1 



CH 2 OH CH 2 OH COOH COOH COOH 



d-glucose d-gluconic d-glucuronic d-saccharic d-mucic 



acid acid acid acid 



These experiments show that the organism of diabetics can decompose 

 in the same way as the healthy organism, substances which in their alde- 

 hydic nature are closely related to dextrose, and are to be regarded as 

 direct oxidation products of dextrose; in other words, a very slight 

 oxidation of the sugar molecule suffices to enable the organism of the 

 diabetic to attack it. In this way the views expressed by Scheremet- 

 jewski, 4 Schultzen, 5 A. Cantani, 6 and of Nencki and Sieber gain ground; 



1 Z. klin. Med. 19 (1890). 2 Z. physiol. Chem. 19, 603 (1894); 19, 629 (1894). 



3 Z. exper. Path. u. Therapie, 2, 53 (1905). 



4 Arbeiten aus dem physiol. Institut zu Leipzig, 1868. 

 6 Loc. cit. 8 Du Diabetes mellitus, Berlin, 1877. 



