18 Notes from the Physiological Laboratory 



1. If whole wheat-grains be macerated in water 

 to which a few drops of ether have been added to 

 prevent germination, they will, in a few days, be- 

 came thoroughly softened, and the contents of each' 

 grain may then be squeezed out as a white tena- 

 cious mass. Examination of the remaining bran 

 shows the "gluten-cells" undisturbed, closely adher- 

 ing to the cortical protective layers. By now care- 

 fully washing the white extruded mass, the major 

 part of its starch may be removed ; and upon the 

 addition of a drop of iodine solution, microscopic 

 examination shows numerous net- works of fine yel- 

 low fibrils, still holding entangled in the'ir meshes 

 many starch-granules colored blue by the iodine. 

 In carefully-washed specimens, these sponge-like 

 net-works are seen to retain the outline of the cen- 

 tral starch-filled cells, and evidently constitute the 

 protoplasmic matrix in which the starch-granules 

 lay. Upon gently teasing such a specimen under a 

 moderate amplification the fibrils will be seen to be- 

 come longer and thinner in a manner possible only 

 to viscid and tenacious substances, a class repre- 

 sented in wheat by gluten alone. 



An eminently satisfactory proof of the proteid 

 nature of these central net-works may be obtained by 

 heating the specimen in the solution of acid nitrate 



