MICROSCOPE IN MANUFACTURES 



cannot make the water go near the wool for the 

 reason that the latter is covered with a film of 

 grease, called wool fat. Our first care, therefore, 

 it to get rid of the wool fat and this may be done 

 by shaking the specimen with a little ether or 

 chloroform. 



Having cleaned the wool fibres we may proceed 

 to examine them under a high magnification and, 

 to see their structure fully, we must move the fine 

 adjustment to and fro, for it is not possible to 

 obtain a true idea of its structure without doing 

 so. We shall see that the hair consists of two 

 layers, an outer skin and an inner core. The latter 

 consists of a number of cells, whilst the former is 

 composed of scales, of which the lower edges are 

 arranged beneath the upper edges of the previous 

 scales, like tiles on a roof. The free edges of the 

 scales project outwards a little so that the wool, 

 when not so highly magnified, appears to have a 

 toothed margin. Further examination will show us 

 that no single scale completely envelops the strand 

 of wool, usually two scales make the complete 

 circuit. It is a curious and easily tested pheno- 

 menon that in say an inch of wool from the same 

 kind of sheep there are always the same number 

 or very nearly the same number of scales. By 

 counting the scales, experts can tell from what 

 animal the wool is derived. 



If we examine many samples of wool we shall 

 not be long before we encounter certain specimens 

 showing one or more constrictions. Now we all 



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