22 



When the boiled starch-grains are washed out during some days with water constantly 

 renewed, it is possible finally to obtain the vesicles without their contents and filled 

 with water only; after drying they weigh 0.4 gr. if one gr. of starch has been used. 

 With iodine they colour lighter than the granulose and somewhat violet. When 

 preserved they become partly soluble in water containing chloroform. By leuko- 

 diastase they are easily converted into maltose and dextrine, quite like granulose; by 

 erythrodiastase a little less easily, but a marked difference does not exist 1 ). 



Explanation of the figure. 

 Magnified 200 times. 



Potato-starch after prolonged boiling and treatment with a tannin solution. The grains 

 are by the boiling changed into little vesicles with dissolved contents. The wall of the 

 vesicles consists of amylocellulose (amylopectose), the contents of granulose (amylose), 



the latter being precipitated by the tannin. 



If the boiling is effected not in distilled but in canal water, the starch shows a 

 strong disposition to precipitate whereby after 24 hours a layer results of 1 / 3 to 

 V* of the whole volume if again i% starch is used. If 4% starch or more is boiled 

 in canal water no sedimentation at all occurs, the swollen grains again touching one 

 another. The precipitation may be caused in the starch boiled with distilled water 

 by addition of dilute solutions of salts, acids, or alkalies. At 0,001 % a slight con- 



l ) By leukodiastase I understand the slowly diffusing diastase secreted by the germs 

 of germinated corn-grains, which on starch-gelatin plates, when treated with iodine, 

 produces diffusion fields which remain uncoloured. By erythrodiastase the more quickly 

 diffusing diastase of the endosperm of the grain, which on the said plates after treating 

 with iodine, is recognisible by the erythrodextrine reaction. Wijsman (De diastase 

 beschouwd als mengsel van maltase en dextrinase, Amsterdam, 1889) called leukodia- 

 stase dextrinase and ervthrodiastase maltase, but these terms are not well chosen. 



