760 TJRINE. 



shaking the contents of the not too narrow test-tube. The recommendation 

 of heating for a longer time in the water-bath, fifteen minutes or more, is to be 

 discarded, as the delicacy of the test is thereby so much increased that it gives a 

 reaction with a physiological sugar content of 0.02 per cent. 



When the amount of sugar in the urine is not less than 0.1 per cent 

 a positive reaction is obtained if the test is boiled for 2-3 minutes and 

 then allowed to stand quietly for 5 minutes. The phosphate precipitate 

 is then black or nearly black. In detecting smaller quantities of sugar 

 0.05 per cent, the test as a rule must be boiled longer about 5 minutes. 



The value of this test lies in the fact that it positively detects small 

 quantities of sugar 0.1 per cent or somewhat less. Like TROMMER'S 

 test it is a reduction test, and shows also certain other reducing bodies 

 besides the sugar. These bodies are certain conjugated glucuronic 

 acids which may appear in the urine. After the use of certain thera- 

 peutic agents, such as rhubarb, senna, antipyrine, salol, turpentine and 

 others, the bismuth test gives positive results. From this it follows 

 that we should never be satisfied with this test alone, especially when the 

 reduction is not very great. 



According to BOHMANSSON and BANG l this test is perfectly reliable 

 if about 10 cc. of the urine is treated with one-fifth volume of 25 per 

 cent HC1 and about 1 vol. moist animal charcoal (or J vol. dry) and shaken 

 for about one minute and then filtered. The filtrate on neutralization 

 with a few cubic centimeters of caustic soda is used for the ALMEN test. 

 The disturbing reducing substances are removed by the animal charcoal, 

 but the sugar is not. 



Fermentation Test. On using this test the process must vary accord- 

 ing as the bismuth test shows small or large quantities of sugar. If a 

 rather strong reduction is obtained, the urine may be treated with yeast 

 and the presence of sugar determined by the generation of carbon 

 dioxide. In this case the acid urine, or that faintly acidified with a little 

 sulphuric or hydrochloric acid, is treated with compressed yeast, or yeast 

 which has previously been washed by decantation with water. Pour 

 this urine to which the yeast has been added into a SCHR OTTER'S gas- 

 burette or a LOHNSTEIN'S saccharimeter (see below). As the fermenta- 

 tion proceeds, the carbon dioxide collects in the upper part of the tube, 

 while a corresponding quantity of liquid is expelled below. As a con- 

 trol in this case two similar tests must be made, one with normal urine 

 and yeast to learn the quantity of gas usually developed, and the other 

 with a sugar solution and yeast to determine the activity of the yeast. 

 According to VICTOROW 2 the fermentation is complete after six hours 

 at a temperature of 34-36 C. 



If, on the contrary, only a faint reduction with the bismuth test is 

 found, no positive conclusion can be drawn from the absence of any car- 

 bon dioxide or the appearance of a very insignificant quantity. The 

 urine absorbs considerable amounts of carbon dioxide, and in the presence 

 of only small amounts of sugar the fermentation test as above performed 



1 Bioch. Zeitschr., 19. 2 Pfluger's Arch., 118. 



