CHAPTER XIV. 



STARCH, CELLULOSE. 



Starch and Cellulose. 



Read : 



WOHL. Ber. d. d. chem. Ges. xxm. (1890). 

 E. SCHULZE. Ber. d. d. chem. Ges. xxiv. (1891). 

 WINTERSTEIN. Zeit. physiol. Chem. xvn. (1892). 

 SCHEIBLER and MITTELMEIER. Ber. d. d. chem. Ges. 

 xxm. 2 (1890); ibid, xxiv. 1 (1891); ibid, xxvi.3 (1893). 



Estimation of Starch. 



A discussion of methods suitable for estimation of 

 starch in leaves and plant tissues will be found in Brown 

 and Morris' paper, J. C. S. LX. (1893), pp. 622633. 



Fair results may sometimes be obtained by using mo- 

 difications of Sachs' iodine method 1 colorimetrically, but 

 it is frequently necessary to resort to ' chemical methods.' 

 These are based on the insolubility of starch in cold water 

 and its solubility in dilute acid, or in an extract containing 

 diastase, cellulose being insoluble under the influence of 

 these reagents. 



1 See Part I, p. 21. 



