[VOL. 6 



100 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



Reducing subst 



the extracts 



Douglas fir aft 



ng and subsequent treatment with 0.5 p 



ph 



acid 



— The purpose of this series is to determine 



hether or not pr 



autoclaving in any way affects the 



rate of acid hydrolysis of woody tissues. 



Flasks containing: Douglas fir sawdust and distilled water 



prepared and 



ed 



before. Enough c.p. sul 



phuric acid was then added to each flask to make it 0.5 per cent 

 acid, and the entire series again autoclaved for 1 hour at 15 

 pounds pressure and the amounts of reducing substances de- 

 termined as mgs. of copper. 



TABLE III 



AMOUNT OF REDUCING SUBSTANCES CALCULATED AS MILLIGRAMS 



IN 10 CC. OF THE EXTRACTS 



Flask no. 



Interval of autoclaving 

 with dist. H 2 



40 

 41 



Not autoclaved 



14 

 15 



45 minutes 



17 

 19 



11 hours 



23 

 24 



21 hours 



Amount of 



reducing substance 



in 10 cc. of 



the extracts 



55.97 

 55.97 



72.22 

 57.08 



58.83 

 58.83 



Average 



55.97 



64.65 



58.83 



61.05 

 63.60 



62.32 



The results here show but a slight increase, if any, in the 

 amounts of reducing substances present in the wood extracts 

 in the flasks regardless of the increased time of autoclaving 

 with distilled water. This may indicate either that prolonged 

 previous treatment with distilled water did not cause any 

 changes in the wood which would make it more subject to acid 

 hydrolysis or that 0.5 per cent sulphuric acid is of sufficient 

 concentration to hydrolyze the wood in any condition. 



dances in the extracts of Douglas fir after 

 subsequent treatment with 1.0 per cent sodium 



Reduc 



sub 



hydroxide. — Flasks containing 2.000 gms. of Douglas fi 

 dust were prepared in exactly the same manner as in tl 



