NONEXISTENCE OF SUSAR IN DIABETIC BLOOI>. 



187 



inconsiderately employed it for other experiments, and coa- 

 gulated it at the same time with the former. 



In the next experiment I added half a dram of the urine 5th experi- 

 of the same person to six drams of the serum, apd,with a due "'^" ' 

 proportion of diluted muriatic acid, coagulated as before. 

 Although the quantity of extract added did not exceed xf» 

 or two grains and a quarter of extract, the difference was 

 very manifest by the darkness of the colour and the defec- 

 tive crystallization of the salts. 



To the remaining quantity of the serum I had added 

 twice the former proportion of the urine, and found that 

 this quantity did not wholly prevent the crystallization of 

 the salts during the evaporation of the drop. 



The result of these trials was such, as to satisfy me, that No sugar in 

 the serum in this instance contained no perceptible quantity 

 of sugar ; or, at least, that the water separable from 

 the coagulated serum did not contain one thirtieth part of 

 that proportion, which 1 had found in the urine of the same 

 person. 



In order to account for the presence of sugar in the urine, Thesrgar 

 we must consequently either suppose a power in the kidneys Sidneys*" 

 of forming this new product by secretion, which does not 

 seem to accord with the proper office of that organ ; or, if 

 we suppose the sugar to be formed in the stomach by a pro- <"■ conveyed to 

 cess of imperfect assimilation, we must then admit the ex- f^om the 

 istence of some channel of conveyance from the stomach to stomach, 

 the bladder, without passing through the general system of 

 blood vessels. That some such channel does exist, Dr. 

 Darwin* endeavoured to ascertain, by giving large doses of 

 nitre, which he could perceive to pass with the urine, but Dr. Darwiit*s 

 could not detect in its passage through the blood ; and he prove'this by 

 imagined the channel by which it was conveyed to be the ab- nitre. 

 sorbent system, upon the supposition, that they might ad- 

 mit of a retrograde motion of their contents. 



Without adopting the theory of Dr, Darwin, it did ap- The author's 

 pear to me, that the fact deserved to be ascertained by some potash*^'*^^ ** 

 test more decisive than nitre, and I conceived, that, ifprus- 



* Account of the retograUe motion of the absorbent vessels, by Charles 

 Darwin. 



siat^ 



