176 KRAEMER — CONTINUITY OF PROTOPLASM. [April 4, 



employed and which bears an analogy to the structure of the 

 starch grain. 



In the author's studies on the starch grain, the following obser- 

 vations have been made : 



(i) The illustrations of potato starch in the various text-books 

 show two kinds of grains, one with the point of growth and the 

 alternate lamellae light in color, as figured by Sachs (Plate XXI, Fig. 

 i), and the other with the point of growth and alternate lamellae 

 dark, as figured by Strasburger (Fig. 2). This appearance, how- 

 ever, is not due to a difference in the grains, but is brought about 

 by the manner of focusing on them. In the figure given by Stras- 

 burger the lamellae are viewed from above, while in the figure of 

 Sachs the view is from below. 



(2) On treating the starch grain with water at different tempera- 

 tures and a number of reagents,* a radiating crystal-like structure 

 is observed in the successive layers (Fig. 5). This crystalline 

 structure appears to be most pronounced in the layers alternating 

 with the point of growth, and is succeeded by the formation of a 

 number of clefts or fissures (Figs. 6 and 7). In potato starch these 

 clefts are more or less feather-like in appearance, and extend from 

 the point of growth through the middle of the successive layers to 

 the periphery of the grain. In wheat starch the fissures extend 

 radially from near the point of growth to near the periphery. 



(3) On treating starch grains with weak aqueous solutions of 

 various aniline dyes, as gentian violet, eosin and safranin, it is 

 observed that the layers which are less crystalline or colloidal in 

 character take up the stains (Figs. 3, 4 and 7). The various clefts 

 and fissures produced in the grains behave toward staining reagents 

 much like the colloidal layers, and they are probably the tracts or 

 channels through which liquids are distributed throughout the 

 grain. 



(4) We further find that these two kinds of layers behave differ- 



* The reagents used were the following: (i) Chromic acid solution (5 to 15 

 per cent.); (2) Calcium nitrate solution (5 to 30 per cent.); (3) Potassium hy- 

 drate solution (one-tenth of i per cent.); (4) Sulphuric acid (10 per cent.); (5) 

 Silver nitrate solution (2 per cent.); (6) Sodium acetate solution (50 per cent.); 

 (7) Potassium nitrate solution (saturated); (8) Potassium phosphate solution 

 (saturated); (9) Hydrochloric acid (5 per cent.); (10) Potassium iodide solu- 

 tion (I to 10 per cent.); (ii) Tannic acid solution (5 to 15 per cent.); (12) 

 Saliva; (13) Taka-diastase (saturated solution) ; (14) Chlor-zinc-iodide solution; 

 (15) Chloral iodine solution and iodine water, equal parts. 



