274 



GROWTH OF PLANTS 



Figure 107. A, X-ray diffraction pattern of cellulose particles from cotton fibers 

 after treatment for 48 hours with the standard solution {American Chemical Society) of 

 cuprammonium hydroxide. B, A similar sample after three months' treatment with the 

 same reagent. C, 3 g of cellulose particles separated by treatment with HCl (sp gr 1.19) 

 produce a mixed mercerized and native cellulose x-ray diffraction pattern after treat- 

 ment for 18 hours in cuprammonium hydroxide. D, 7 g of cellulose particles similar to 

 those used in C produce a native cellulose x-ray diffraction pattern after treatment for 

 18 hours in cuprammonium hydroxide. 



particles are distributed at random, with no tendency toward fibril forma- 

 tion. The x-ray diagram of the cellulose in this membrane (Fig. 108) 

 shows that it is in a "mercerized" state, comparable to that produced in 

 the cellulose of a cotton fiber when it is treated with strong (17 to 18 per 

 cent NaOH) alkah.^s 



In the protoplasmic mounts of Halicystis were found the structures 

 which had long been the object for which we had searched — either the 



