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Dr. H. Bence Jones on the production 



[Dec. 15, 



The combustion may be made imperfect in at least three different ways : 

 — First, by insufficient oxygen. Secondly, by overwhelming fuel. Thirdly, 

 by reducing the temperature so low that chemical action is checked. 



From each of these causes the following scale of the combustion of starch 

 in the body may be formed. 



When there is perfect combustion, then carbonic acid and water are 

 produced. With less perfect combustion, oxalic and other yegetable 

 acids are formed. With the least possible combustion sugar results. 



Between perfect combustion and the most imperfect combustion (that is, 

 between carbonic acid and sugar) there are probably many steps, formed by 

 many different acids ; and as in a furnace one portion of the coal may be 

 fully burnt, whilst other portions are passing through much less perfect 

 combustions, or are not burnt at all, so different portions of starch may 

 reach different steps in the scale of combustion, and sugar, acetic acid, 

 oxalic acid, carbonic acid, and many other acids between acetic and oxalic 

 acid may be simultaneously produced. 



From this account of the oxidation of starch, it follows that sugar should 

 always be found in the urine whenever any of the three causes mentioned 

 reduce the oxidation in the system to its minimum. In other words, by 

 stopping the combustion that occurs in the body, diabetes should be pro- 

 duced artificially. 



It has long been known that an excess of sugar taken into the blood by 

 injection causes temporary diabetes. This is imperfect combustion from 

 excess of the combustible substance. 



The diabetes of old age, of pregnancy, and after the inhalation of 

 chloroform, may be considered as arising from imperfect combustion in 

 consequence of a deficiency of oxygen. Bernard's diabetes from injury of 

 the floor of the fourth ventricle probably belongs to this cause. 



The third mode of checking the chemical actions in the body is by re- 

 ducing the temperature. This has not yet been proved to cause diabetes, 

 though it ought as surely to stop oxidation as excess of fuel or insufficiency 

 of oxygen. 



The simplest experiment consists in placing an animal in ice. The cold 

 soon deprives it of feeling, and perfect insensibility is produced. My friend 

 Dr. Dickinson undertook to give me the urine of rabbits before they were 

 placed in ice, and after they had died from the effect of the cold. 



Experiment 1. — This lasted one hour and twenty-three minutes. The 

 cold was very carefully applied ; fresh ice was added from time to time. 

 The temperature in the rectum fell from 103° F. to 73° F. In the liver 

 immediately after death the temperature was 76° F. The urine made im- 

 mediately before the application of cold gave no perceptible trace of sugar 

 with sulphate of copper and liquor potassse. The urine collected after death 

 gave marked reduction with these reagents, and when boiled with liquor po- 

 tassse alone it deepened in colour. The acid reaction also was distinctly more 



