DIABETES SUGAR. 



SECTION III. - OF DIABETES SUGAR. 



It is now universally known that in the disease called dia- 

 betes, the urine contains a considerable quantity of sugar, which 

 may be easily extracted in a state of purity. The sweet taste of 

 diabetic urine, and, of course, the existence of sugar in it, seems 

 to have been first observed by Dr Willis. Sydenham, though he 

 describes the disease, and distinguishes it by the name of diabe- 

 tes, takes no notice of the sweet taste of the urine, but only of 

 its great quantity.* The first person who attempted to obtain the 

 sugar in a separate state was Mr Cruikshanks. He gives an ac- 

 count of his experiments in an appendix to Dr Rollo's book on 

 Diabetes, which was published in 1797. He extracted from dia- 

 betic urine about one- twelfth of its weight of a sweet tasted ex- 

 tract like honey. 



In 1815, Chevreulf analyzed diabetic urine, and extracted 

 from it the sugar in a state of purity. He found that the shape 

 of the small crystals which it formed (small spherules) was pre- 

 cisely the same as that of grape sugar. It possessed all the 

 qualities of that sugar, has the same solubility in water and alco- 

 hol, and like grape sugar melts when exposed to a gentle heat. 

 From these facts, Chevreul concluded that diabetic sugar was 

 precisely the same with that of grapes. Cruikshanks had already 

 compared it to honey ; and we now know that sugar of honey is 

 identical with that of grapes. M. Calloud| found diabetic and 

 grape sugar to agree also in another property, namely, that of 

 combining with common salt and forming crystals which have the 

 form of dodecahedrons composed of two six-sided pyramids 

 applied base to base, or sometimes of rhomboids. According to 

 Calloud these crystals are composed of, 



Common salt, . 8.3 



Sugar, . . 91-7 



- 



100- 



This differs essentially from Brunner's analysis, which I have 

 given in the Chemistry of Vegetables, p. 638. Calloud's analy- 

 sis would indicate four atoms of sugar to one of common salt, while 

 Brunner's make the compound to consist of an atom of each con- 

 stituent. But when he combined common salt directly with 



* Opera, p. 271. t Ann. de Chirn. xcv. 319. 



Jour, de Pharmacie, xi. 562. 



