172 A. J. Ewart: 



tetroses or hexoses were formed directly from biose produced in thie- 

 (vay, the percentage polymerization by weight would be the 

 same. If, however, pentoses and hexoses were formed by the direct, 

 linking of formaldehyde to the glycoUic aldehyde, without further 

 production of formates and methyl alcohol, the polymerisation 

 ratio for pentose would be 9 :5 (45%), and for glucose would be- 

 10 :6 (-60%). If a dissaccharide were produced, the maximumi 

 ratio would be 16: 12, i.e., 75%. 



A monovalent alkali such as sodium hydrate can react with single 

 molecules of C^H^Oo, producing sodium formate and methyl alcohol, 

 and will only produce a biose when 2 of sodium hydrate react with 

 2 of C3H,,02, with a third molecule interpolated. The chance for- 

 tius grouping is not more than half what it is in the case of a diva- 

 lent alkali, where a single molecule reacts with not less than 2 mole- 

 cules of C2H4O2. 



Methods. — The same result is not produced when the liquids are^- 

 mixed cold, and then heated, as when the sodium hydrate is run into 

 the boiling liquid. Ihus 250 c.c. of water, with 5 c.c, of 10% 

 calcium formate and 4 c.c. of 25.2% formaldehyde, after raising- 

 to the boiling point required, 7.2 c.c. of 3.5% NaHO to complete 

 the reaction. If mixed cold with 7 c.c. of sodium hydrate, on rais- 

 ing to the boiling point a further addition of 0.4 c.c. of NaHO was 

 required to complete the reaction. If mixed cold with 7 c.c. NaHO, 

 and kept for 15 days at 15° C, on raising to the boiling point, the 

 addition of a further 1.2 c.c. of NaHO is required to complete the 

 reaction, And remove all CUfi. Hence at low temperatures more 

 formats is produced and less formaldehyde is polymerised to sugar, 

 so that more soda is required to remove all the formaldehyde. 



In carrying out estimations, a preliminary test was in each case 

 carried out in an open beaker. The amount of sodium hydrate re- 

 quired was less than the full amount by the amount of CHgO lost 

 during the boiling. The same amounts of CHi,0, water and cal- 

 cium formate, ^yere then placed in a flask fitted with a condensing- 

 apparatus, so that the condensed steam washed back the. escaping 

 formaldehyde. The amount of sodium hydrate previoiisly noted' 

 was then run in from a burette fitted to the cork, as rapidly as 

 was possible without causing too violent ebullition. 



The yellow tinge which indicates the completion of the reaction 

 appears slowly with very dilute solutions, and the preliminary test 

 must be checked by smell as well as colour. With strong solutions- 

 the -yellow colour is produced before the reaction is completed, if 



I 



