22 0?^ tJie Non-existence of Sugar in the Blood. 



Ivsed, and fouml to contain sugar. This blood had been 

 dried, when fresh, by a gentle heat, so as not to coagulate 

 the serum. After being reduced to powder, it was mixed 

 with water, in order ihat every ihiiig which remained so-' 

 luble might be extracted. A little muriatic acid was then 

 added, and sufficient heal applied for coagulation of the 

 albumen. The water that separated after coagulation was 

 found to contain the salts of the blood, buc ao trace what- 

 ever of sugar. 



A second specimen of dried blood, that had been ascer- 

 tained to be diabetic on the same evidence as the preceding, 

 was examined in a similar manner, with the same result, as 

 r.o appearance of sugar could be discerned. 



In a third instance, I had some serum from the blood of 

 a person whose urine had been tasted, and found " ver}j 

 sweet." (I had no opportunity of procuring any of this 

 urine for analysis.) After a portion of this serum had been 

 coagulated, with the addition of the usual proportion of 

 muriatic acid, there was no appearance whatever of sugar. 

 But when three grains of diabetic sugar had been added to 

 another ounce of the same serum, the presence of this 

 quantity was manifest by the same process. 



I had also a fourth opportunity of exannning serum of a 

 person whose urine contained so much Saccharine matter, 

 that an ounce of it yielded, by evaporation, thirty-six grains 

 of extract. In this instance I was not so successful in my 

 experiment ; for, though I was satisfied that no sugar was 

 present, there certainly was a degree of blackness, which 

 might have been occasioned by about one grain and a half 

 of sugar in the ounce of serum. But this black matter ap- 

 peared not to be sugar : it v. as more easily dried than sugar: 

 it was not fusible by heat, as sugar is: and its refractive 

 power* was too great for that of sugar. 



I unfortunately had no opportunity of repeating the ex- 

 periment on a second portion of the same serum, having 

 inconsiderately employed it for other experiments, and co- 

 agulated it at the same time with the former. 



In the next experiment I added half a drachm of the 

 urine of the same person to six drachms of the serum, and 

 with a due proportion of diluted muriatic acid coagulated 

 as before. Although the quantity of extract added did not 

 exceed -;C, or two grains and a quarter of extract, the dif- 

 ference was very manifest bv tlie darkness of the colour and 

 the delectivc crystallization of the salts. 



• The method \ty which this w;i« 'rierl lias sliice tliat i.mt been de-cribgii 

 in the Philn'ophical Tran5acticns (or ISOi!. . 



" .... To 



