FIBERS (TEXTILE) 



(c) Chevron: This pattern consists of 

 waves, usually regular, but some 

 times irregular, with either the crests 

 or the bottoms of the -troughs or both, 

 relatively narrow and V-shaped. 

 There are two varieties of chevron 

 pattern, namely. 



Single chevron: in which only one of 



the crests or troughs is narrow and V- 



shaped. 



Double chevron: in which both the 



crests and the bottoms of troughs of 



the waves are narrow and V-shaped. 



(d) Pectinate (comblike) : The term is seK 

 explanatory, but two basic varieties 

 are recognized. 



Coarse pectinate describes the pat- 

 tern in which the "teeth" of the comb 

 are relatively large and set wide apart. 

 Lanceolate is the pattern in which 

 the teeth of the comb are long, narrow 

 and rather more pointed than in the 

 coarse pectmate type. 



(e) Petal patterns: The general appear- 

 ance of these resembles a series of 

 overlappmg flower petals due to the 

 imbricate or overlapping appearance 

 of the scales. There are several varie- 

 ties of petal patterns and they are 

 really modified wave forms, some- 

 times interrupted, regular waves and 

 sometimes interrupted irregular 

 waves. It must be clearly understood 

 that a pattern does not qualify as a 

 petal pattern unless its appearance 

 strongly suggests a series of overlap- 

 ping or imbricate elements. 

 Irregular petal: This is a form of in- 

 terrupted irregular wave. 

 Diamond petal: The wave crests over- 

 lap the troughs of the succeeding 

 series of waves toward the tip end 

 of the fiber. 



With the aid of this scale system it is cer- 

 tainly possible to identify the types of hair, 

 especially if intermediate forms are con- 

 cerned and the differences between root end, 



shaft and tip of the hair are examined sepa- 

 rately. The medulla of fibers can be used for 

 identification in only a few cases. We can 

 distinguish : 



1. Continuous thin medulla — diameter 

 <32 the fiber diameter. 



2. Continuous full medulla — diameter 

 > }-'2 the fiber diameter. 



3. Continuous, regularly pectinate. Cell 

 partitions divide the medulla into regu- 

 lar chambers 



(a) chambers in one row 



(b) chambers in several rows. 



4. Continuous spiral. 



5. Interrupted at regular intervals, pre- 

 dominant type. 



6. Interrupted at irregular intervals, pre- 

 dominant type. 



7. Sporadic types. 



8. Irregular shapes. 



Many of these types occur with one kind 

 of fiber. Only 2, 3 and 4 have any systematic 

 significance. 



Structure of Wool and Other Animal 

 Hair (Figs, la and lb). 



In general animal hair consists of the fol- 

 lowing parts: 



The medulla, the innermost part of the 

 hair, recognizable by less elongated cells not 

 highly pigmented. After cornification, fairly 

 large air cavities occur in the medulla, which 

 may help to bring about the color of the hair 

 (interference colors). As a rule the medulla 

 is fairly easy to see in wool preparations. 



The cortex, a zone consisting of spindle- 

 shaped cells. Each of these cells is enveloped 

 in membrane about 500 A thick. The con- 

 tents consist of fibrils (tonofibrils). These 

 tonofibrils are well oriented along the fiber 

 axis. In between the fibrils there is an evap- 

 orated protein substance, the cement. The 

 tonofibrils consist of keratin. The cortex 

 outer layer is formed by a less oriented fibril- 

 lary mass: the cortex mantle. This cortex 

 mantle forms a screen in the fiber against the 

 penetration of dyes and chemicals. 



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