GENERAL MICROSCOPY 



fiber identification are the strongly pebbled, 

 crenelated skin cells. 



Esparto pulp. This pulp is made from tlie 

 leaves of Stepa tenacissima and Ly genus 

 spartus. This pulp consists mainly of short, 

 thin bast fibers closely resembling flax. But, 

 here again like straw, the X-shaped displace- 

 ments are lacking, while the fibers are hardly 

 damaged even when pulped. These bast 

 fibers are considerably thinner than those of 

 straw. Small, sac-like skin cells are found 

 throughout the specimen. The parenchyma 

 cells, which are also present to a considerable 

 extent, are usually badly damaged by pulp- 

 ing. The specimens also contain pieces of 

 annular and spiral vessels and also short bits 

 of hair, shaped like commas, which are very 

 useful for a diagnosis. 



It is difficult to estimate the percentage 

 of esparto pulp mixtures which also contain 

 straw pulp. After staining with Rhodamine 

 6 GD/Coriphosphine, an estimate is possible 

 with the aid of the secondary fluorescence. 

 Straw pulp fibers give a yellow green color 

 and esparto a brownish green color. 



Ampar (Bagasse). This pulp is made from 

 the sugar-cane waste. Characteristics of this 

 paper material are finely porous parenchyma 

 cells and differentially formed sclereides. 

 The bast fibers have the following forms: 

 (a) greatly thickened, fairly wide fibers 

 (approx. 20-30 fx). (b) short, uniformly wide 



fibers with thin walls, (c) narrow, tapering 

 fibers largely resembling straw fibers. 



The skin cells differ greatly in size and are 

 not frequently found; they are usually 

 badly damaged. 



Ground wood. The ground wood mostly 

 found is soft wood. In Italy ground poplar 

 is often also incorporated in paper. Under 

 the microscope the normal image of soft 

 wood or hard wood anatomy is recognizable 

 in the ground wood particles. 



Ground soft wood is characterized by the 

 wide fiber tracheides with their almost roimd 

 bordered pits. Crosswise to these tracheides 

 are the medullary rays built up of narrow 

 and fairly long parenchyma cells. The drop- 

 lets of resin characterizing soft wood are 

 usually easy to see. Characteristic of groimd 

 hard wood are the large vessels and the ab- 

 sence of pits. 



Pulped Fiber. The morphology of fibers 

 is greatly changed by pulping, the extent 

 depending upon the degree of pulping and 

 on the type of pulping machine. On the whole 

 the changes are fairly great in the case of 

 rags, hard wood and soft wood. Straw and 

 esparto pulps change to a less extent. In the 

 case of highly pulped material it may often 

 be difficult to distinguish the various kinds 

 with a microscope. Staining methods are 

 then often fairly difficult and are conse- 

 quently of little value as evidence. 



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