142 ESSENTIALS OF CHEMICAL PHYSIOLOGY 



I. CHaOH [CH(0H)]3GH(0H)C0H + H2N.NH(C,jH5) 



[dextrose] [phenyl-hydrazine] 



CH2OH [0H(0H)]3CH(0H)CH- 



II +H2O 



N-NH(C«H,) 



[hydrazone] [water] 



II. CH20H[CH(OH)]3CH(OH)CH 



II +CCH5.NH-NH2 



N-NH(CoH,) 



[hydrazone] [phenyl-hydrazine] 



CH20H[CH(OH)]3C - CH 



II II -hH, + H2O 



[osazone] [hydrogen] [water] 



5. Barfoed's Reagent. — Dissolve 1 part of cupric acetate in 15 parts of 

 water ; to 200 c.c. of this solution add 5 c.c. of acetic acid containing 38 per 

 cent, of glacial acetic acid. Dextrose reduces this reagent on boiling ; mal- 

 tose and lactose do not. This test is not very delicate. 



6. The Polarimeter. — Estimate the strength of a solution of dextrose by 

 means of the polarimeter (see Appendix). 



