THE MONOSACCHARIDES 5 
Grlycuronic acid. — If saccharic acid is heated five or six hours in the 
water bath, it is changed into saccharo-lactonic acid, C 6 H 8 7 . If this is 
reduced by means of sodium amalgam, one obtains glycwronic acid] 1 this 
Bubstance is of considerable interest hecause it is sometimes found in the 
body, and when it passes into the urine is apt to he mistaken for sugar, 
many of the tests for which it gives. 
Its composition is — 
( < )< )H— (( H.OH ) — CHO = C 6 H 10 O 7 
It is soluble in water and alcohol, is dextro-rotatory, reduces alkaline 
solutions of metallic salts, and yields saccharic acid on oxidation with 
bromine. It does not undergo the alcoholic fermentation. Though 
related in its composition so nearly to the carhohydrates, it yields with 
urea decomposition products which are aromatic, such as orthonitro- 
benzyl alcohol (Jaffe). 2 It occurs in the urine in the form of the 
potassium salt (C e H u 7 K) after the administration of chloral and 
butylchloral, 3 nitrobenzol, 4 orthonitrotoluol, 5 camphor, 6 etc. It also 
occurs in the urine after chloroform narcosis, and in the paralytic 
secretion that takes place on section of the renal nerves. 7 Occasion- 
ally it is found without any apparent cause, as a result of disordered 
metabolism. 
Levulose on oxidation always yields acids containing less carhon 
atoms than itself, namely, trioxybutyric (CH.,OH(CROH).,COOH), 
formic (H.COOH), and glycollie (CH 2 .OH.COOH) acids. But different 
acids are yielded 1 >y different methods of oxidation ; thus chlorine or 
1 iromine and silver oxide oxidise levulose to glycollie acid ; s nitric acid 
yields oxalic, tartaric, glycollie, acetic, and other acids. 9 
Synthesis of sugars. — The first step towards the synthesis of the sugars 
Avas made by Butlerow. 10 He obtained a sugardike substance by adding lime 
water to a solution of dioxymethylene ; this he termed methylenitan, 
and gave its formula as C 7 H 14 <; . Loew n next obtained a condensation 
product of formaldehyde (CH L ,0) by means of lime water ; to this substance 
he attributed the formula (C r H 12 0,;), and called it formose. 
Xeither methylenitan nor formose ferment with yeast. Fischer 12 
investigated these substances, and found that they were mixtures of two 
sugars, one of which is formose (C (3 H 12 G ), and another a-acrose 13 (C H 12 O G ), 
both of which yield crystalline osazones. 
From the osazone which is yielded by a-acrose the sugar can be again 
1 H. Thierfelder, Ztschr. f. physio!. Chem. , Strassburg, 1887, Bd. xi. S. 388; 1891, Bd. xv. 
S. 71 ; Ber. d. deutsch. chem. Gesettsch., Berlin, 1886, Bd. xix. S. 3148; E. Fischer and 
0. Piloty, ibid., 1891, Bd. xxiv. S. 521. 
3 Ztschr. f. physiol. '.'hem., Strassburg, Bd. ii. S. 47. 
3 Musculus and v. Mering, Arch. f. d. ges. Physiol., Bonn, Bd. xx. S. 64. 
4 v. Mering, Centralbl. f. d. med. Wissensch., Berlin. 1875, No. 55. 
3 Jaffe, loc. cit. 
6 Schmiedeberg and Meyer, Ztschr./. physiol. Chem., Strassburg, Bd. iii. S. 422. 
7 Ashdown, Brit. Med. Journ., London, 1890, vol. i. p. 171. 
8 Hlasiwetz and Haberniann, Ann. d. Chem., Leipzig, Bd. civ. ; Kiliani, ibid., Bd. 
elv. S. 175. 
9 Kiliani, ibid., S. 162 ; Hornemann. Journ. f. prakt. Chem., Leipzig, Bd. lxxxix. S. 283. 
1,1 Ann. d. Chem., Leipzig, Bd. exx! S. 295 ; Compt. rend. Acad. d. sc., Paris, tome lii. 
p. 145. 
11 Journ. f. prakt. Chem., Leipzig, Bd. xxxiii. S. 321. 
12 Ber. d. deutsch. chem. Gesellsch., Berlin. Bd. xix. S. 2133. 
13 Acrose is a sugar obtained by Fischer, ibid., Bd. xx. S. 1093 and 2566, by acting on 
acrolein bromide with bases (2C3H 4 OBr : , + (2Ba(OH) 2 = C 6 H 1 ,0 G +2BaBi\, ; two isomeric 
sugars, a- and /3-acrose are thus produced. 
