144 THE MICROSCOPE. 



activity, and become a reserve, either in the seed for the needs of 

 the young plantlet, or in leaves, bark or substance for a time of 

 scarcity. 



Among the products laid up in store, starch is undoubtedly the 

 most abundant and important ; it is found in all the higher classes 

 of plants and in many, perhaps most of the lower. It supplies to 

 animals a very large proportion of the food derived from the vege- 

 table kingdom, and probably to the fact that mankind has been 

 able to enormously develop the starch producing power of the 

 cereals is largely due his own elevation from savagery to civilization. 

 Deprive the race of the starch reservoirs found in wheat, maize, rice;, 

 and their congeners, and how long could the enlighted races main- 

 tain their supremacy ? The last two or three years have well nigh 

 proved that wheat is king of Europe. A few facts in regard to the 

 development of the starch-grain then, will interest you for a few 

 minutes. 



To Nageli and Sachs we owe most of what is known of this sub- 

 ject. From a recent paper in the Quarterly Journal of Microscopical 

 Science by Mr. A. F. W. Schimper, and from Sachs' Text Book of 

 Botany I have mainly derived the material offered you. 



Starch, as such is not directly available for nutriment; it is a 

 substance comparatively stable, though under conditions of 

 heat and moisture and in the presence of a proper ferment it be- 

 comes transformed into soluble sugar, and then is appropriated by the 

 elaborating organs of the plant ; familiar instances will occur to you 

 at once in the various grains. When the seed is planted, the moisture 

 and heat of the proper season enable the ferment existing in 

 the seed to convert the starch into sugar, which goes directly to the 

 growing germ, supplying it with food before it yet has roots adequate 

 to draw nutriment from the earth. Tuberous roots, as the potato and 

 arrowroot, present a similar provision except that here a young 

 sprout is the subject to be supplied. In the potato bin, in the 

 spring it is common to find the old potato shriveled and deprived 

 of its starch to supply a tall etiolated sprout, with scarcely any root 

 to support it. 



Starch presents the same general characteristics wherever found 

 though it varies much in the size and shape of its grains, and while 

 the subject has as yet been comparatively little studied, observers 

 recognize at least two methods in its production: First, as seen in 



