c.lOO^' 



104 FUNDAMENTALS OF SUBMICROSCOPIC MORPHOLOGY I 



crystallizes in submicroscopic hexagonal needles which all run parallel 

 to the fibres axis, for, instead of a Debye-Scherrer diagram, 3. fibre 

 diagram of silver amalgam is obtained. This proves the presence of 

 submicroscopic canals in the fibre. 



It is much more difficult to discover the dimensions of these pre- 

 formed capillaries, as the size of the gold crystals embedded varies 



with the speed at which 

 they develop in the capil- 

 lary system. Furthermore, 

 the metal rodlets causing 

 the dichroism are so large 

 that they can easily be 

 shown in the ultramicro- 

 scope (Fig. 72). Their rod- 

 shape is betrayed by the 

 different intensity of the 

 light scattered in lateral 

 irradiation according as 

 the vibration of the line- 

 arly polarized light is par- 

 allel or perpendicular to 

 the fibre axis (Frey-Wyss- 

 LiNG, 1937b). Consequent- 

 ly, the crystals or primary 

 particles measured by 

 means of X-rays must have clustered together to form rod-like aggregates 

 or secondary particles (Fig. 73), widening the capillaries in so doing. 

 Whether this already takes place while the crystals are growing, we 

 do not know. Presumably, however, they can develop fairly freely, 

 since they do not acquire the rodlet shape of the capillary system until 

 they are collected in the secondary crystalline particles. We must there- 

 fore take it as proved that, apart from the intermicellar spaces in which 

 the water penetrates when the fibre swells, there exist even larger pre- 

 formed inhomogeneities . 



As a consequence, native fibres must possess long-shaped submi- 

 croscopic regions containing intermicellar spaces which are only 

 accessible to small molecules such as water, salt ions and iodine. These 

 regions are designated as microfihrils\ they possess a more or less homo- 



Fig. 72 



Fig- 75 



Fig. 72. Ramie tibre stained with silver in the ultra- 

 microscope (from Frey-Wyssling, 1937b). 

 Fig. 73. Ultrastructure and shape of the submicro- 

 scopic silver rodlets in the fibre. 



