MF,T.\IU)I,ISM IN' LIVINT. PLANTS. 



459 



hydrate at certain points in the interior of its substance as well as at its periphery, 

 in addition to another carbohydrate, the so-called fjranulose. Cellulose and fjranu- 

 lose, very intimately intermixed, appear in the form of grains, and the mixture is 

 called starch or amylum. Stareh-grains are among the commonest of cell-contents. 

 They appear i-egularly in chlorophyll-bodies and are conveyed from the places where 

 the}' are fii-st formed to all parts of the plant, 'i'liis of course is only etlected liy 



Fig. 124.— Various Forms of Starch -grains. 





* From the seeds of the Com-cockle (Agrostemma Qithago). 3 From a grain of Wlieat. * From Spurge, * From a liean seed. 

 » From a grain of Maize. « From tlie root-stock of Caniia, ' From a Potato-tuber (inclosed in cells). * From a Potato- 

 tuber (isolated and very highly magnified). * F'rom a grain of Oats, lo FYom the seed of Lolium temulentum. ii From 

 the corm of the Meadow .Saffron (Colchictiin aiUumnaU). " From a grain of Rice. ^8 From a grain of Millet. All highly 

 magnified. 



the solid stjirch bodies being made fluid, as often as they pass from one cell to 

 another, by the help of an accessory substance, called diastase, which has yet to be 

 described. In many tissues the starch-grains become so accumulated that the cells 

 appear to be crammed with them (see fig. 124 "). Starch is one of the most important 

 of reserve materials, i.e. of those materials which are not consumed immediately 

 after their formation, but are put away for a time in store-rooms or reservoira, and 

 then consumed as required in tlic places needing them. For example, they may 



