BY DR. LAUDER BRUNTON. 509 



in the other piece, this sugar must have been formed after the 

 liver was cut in pieces. 



The Liver contains Glycogen, a Substance which can be 

 changed into Grape Sugar by the action of Ferments. Take 

 a little of the milky nitrate obtained by boiling the liver which 

 has been already found to contain no sugar. Add to it a little 

 saliva, and let it stand in the water-bath at 35 C. for a few 

 minutes, or warm it gently over a spirit-lamp. Then add liquor 

 potassoe and ctipric sulphate, and boil ; sugar is found. Evapo- 

 rate the milky remainder of the nitrate to a small bulk, and 

 add alcohol in excess. A white flocculent precipitate of gly- 

 cogen is formed. 



The Liver also contains a Diastatic Ferment. From the 

 other piece of liver which has been placed in alcohol prepare a 

 glycerin solution, as directed in' 160. Add some of this to a 

 solution of glycogen, let it remain in the water-bath at 40 C., 

 and test small portions of it from time to time. Sugar will at 

 length be found, but very many hours may be necessary. 



155. Mode of Testing for Sugar in Blood. As the 

 albumin and coloring matter of the blood would interfere with 

 the reaction, they must be removed before the test is applied. 

 Bernard's method is as follows: Put the blood, if pure, in a 

 mortar, and rub it up with a quantity of animal charcoal, suffi- 

 cient to form a dry paste. Add a little water, rub it up again, 

 and throw the mixture on a filter. The water filters through 

 quite clear, holding in solution any sugar which may be pre- 

 sent, and Trommer's test may then be applied to it. If the 

 blood is diluted, agitate it well with sufficient animal charcoal 

 to form a thick paste ; filter it, and test as before. 



Another method, which is preferable if the quantity of sugar 

 is to be estimated, is to mix the blood with three or four times 

 its bulk of strong spirit, and after allowing it to stand for some 

 time, to filter. The residue is then extracted with much alco- 

 hol, and after the addition of the extract to the filtrate, the 

 alcohol is evaporated off and the residual liquid tested. Trom- 

 mer's test answers for saliva, but in the present case it is inade- 

 quate, as many other bubstances capable of reducing cupric 

 oxide might be present. Other tests are therefore required. 



Moore's Test. Put the solution in a test-tube and add suffi- 

 cient liquor potassse or liquor sodae to make it strongly alka- 

 line. Heat it gently to boiling. If sugar is present in con- 

 siderable quantity, the fluid will become first yellow, then 

 reddish-brown, and, lastly, dark brown or black ; but if there 

 is only a little sugar, the color will only become yellow or red- 

 dish-brown. 



Bb'ttchers's Test. Put the solution in a test-tube, and add to 

 it as much bismuth oxide or subnitrate as will lie on the point 

 of a knife, and a considerable excess of a very strong solution 



