THE STARCH CELL. 



39 



filled with, amorphous (?) starch ; that the concentric striae visible in the granule indi- 

 cate the surfaces of contact of these lamellae ; and that the so-called nucleus of Fritzsche 

 corresponds to the central cavity. 



2nd. That while the lamellae appear to be all identical in chemical constitution, 

 yet the internal differ from the external in consistency or other conditions of inte- 

 gration. 



3rd. That the order of deposition of the lamellae is centripetal. 



4th. That while the starch granule is thus a lamellated vesicle, it cannot be included 

 in the category of the true vegetable cell, from which it dffers, not only in the absence 

 of a propei nucleus, but in presenting no chemical differentiation between membrane 

 and contents. 



So widely do equally eminent observers disagree in their description of the same 

 object as seen by the same means ! 



Rice (Fig. 78 a) is known by the small size of its grains, by their angularity, and 

 the absence of evident markings. 



Sago starch (Fig. 78 b] is very much larger than that of rice, but still less than 

 that of wheat ; it is rounded, and its surface is rather granular than plaited. 



Wheat starch (Fig. 78 c) occupies a medium position in point of size, and is more 

 regularly round than any grain of similar size. Its markings are not so distinct as 

 those of the potato. 



Potato starch (Fig. 78 d) is distinguished from wheat starch by its large size 

 irregularity of outline, and flattened lenticular figure. The plaitings on its surface are 

 very distinct, as is also the hilum around which they are gathered. 



Pea starch (Fig. 78 i) is in size about equal to that of wheat; but it differs 

 remarkably in its flattened figure and the star-like plaits which invariably occupy its 

 centre. 



Tous Us mots (Fig. 78 g] is the largest of all known forms of starch, and from its size, 

 void figure, and concentric rings, is not unlike a cocoon. It has occasionally two 

 hilums or holes, and its markings are usually very regular. This article enters largely 

 into the commerce of the day. 



The starch grains, found in the Euphorbias (Fig. 82 a) are very characteristic, and 

 are readily distinguished by their dumb-bell form 

 from those of any other plant. The same grains 

 are seen in Fig. 82 A, floating in the milky juice 

 of the laticiferous tissue. 



Wheaten flour, when adulterated with inferior 

 starch, is usually mixed with potato, pea, or rice 

 starch, each of which may be distinguished under 

 the microscope. So also with wheaten bread, if 

 the smallest crumb be broken up in water, and 

 examined in the ordinary way. 



It is not known if the varieties of starch 

 possess any variation in the degree of their nutri- 

 tive properties. It is therefore the quantity of pure 

 starch which any substance can yield, conjoined 

 with the abundance and ease with which the sub- 

 stance may be obtained, that gives the market- 

 able value. It is also of importance to determine the state of perfection of any 



Fig. 82. Starch cells in the EUPHORBIAS. 

 6, floating in the milk vessels. 

 a, greatly magnified, so as to show their 

 dumb-bell figure. 



