48 



From the nature of the methods followed, it should be remembered here 



part, must also be the compounds of pentosan. Hence in discussing the 

 results, we take the pentosan only into account, neglecting the other entirely. 

 From the results obtained we notice the following : 



1. Pentosan suffers m wt in retting process. 



2. A small quantity of cellulose is also lost, after the middle period 

 of retting. 



3. Pectin is not completely lost. This is apparently iu contradiction to 

 the results of Omelianski, but our experience tends to show that 

 Omelianski used too small a quantity of the sample, making his 

 results rather donbtfnL 



4. Glucose and tannin are completely lost in the retting. 

 Pentosan-free fiber consists of cutin, cellulose and lignin. Attempt was 



made to determine the three components separately by Konig's method, but 

 unfortunately it was found impossible to oxdize lignin with hydrogen 

 peroxide, hence the attempt was given up. Concerning the nature of the 

 changes in pentosan-free fiber we must therefore depend upon the results of 

 microchemical observations. 



To know whether the Changes above mentioned take place in the bark 

 portion or woody portion of the stem, the following experiments were per- 

 formed. The stem was carefully divided from the cambium layer into two 

 parts, i. e., bark and woody portions and weighed. The results are as follows : 



t portion. j Woody ] 



» the retted stem the proportion of the bark porti 



