THE JOURNAL OF PHARMACOLOGY. 215 



base the structure of the hair is similar to that of the middle save that the 

 thickness (75 !') is somewhat less. " But about one centimeter above the 

 base the medullary cylinder disappears, here the fiber is 45 // thick, the 

 scales become more transverse, without becoming distinctly imbricate. 



Ordinary Bohemian Domestic Wool. — A reported not cultivated sort 

 consists of 4 to 5 cm. long, 30 to 40,". thick, uniformly coarsely sinuous 

 wool hairs, entirely with a medulla. The epiderm consists of half to en- 

 tirely cylindrical strongly transverse cells, with a smooth not indented 

 front edge, which is conspicuously thickened. The wool fibers are not 

 circular, very unevenly thick, the edge is irregularly and sharply serrate. 

 The fibrous sheath is regular, and straight coar.sely striate. 



These descriptions must suffice to show in which ways the different 

 sheep wools vary in their microscopical characters. Of course all transi- 

 tional forms that can be imagined may occur among those described. 



Taken collectively the following deductions may be made concerning 

 the microscopical characters of sheep's wool : 



Length 2 to 50 cm., entirely straight to finely curled or spiral, regularly 

 to irregularly curly. Lustreless to glossy, 5 // to over 100 /^. thick. With 

 or without medulla and medullary isles. Medulla if present may consist 

 of I to 4 rows of cells. These cells are round or long to linear, seldom 

 broader than high and always containing fine granular masses and air. 

 The medullary cells are never entirely regular in arrangement. Medullary 

 strand very narrow or occupying four-fifths the thickness of fiber. Fibrous 

 sheath very thin or occupying the whole breadth of fiber, hardly striate to 

 irregularly or regularly fine to coarsely striate. Epiderm may consist of flat 

 to concave, isodiametric to elongated or transversely broader, often half to 

 entirely cylindrical scales which either are arranged as plates or are more 

 or less distinctly imbricate. The front edge of the scales is generally dis- 

 tinctly thickened and very refractive, usually smooth but often drawn out 

 so as to become toothed or (seldom) frayed dentate. The natural tip is 

 generally lacking for they are only present in the first shearing. Lamb 

 wools, and are therefore called lamp-tips. Fig. 8, a, represents one. They 

 generally have imbricated half to entirely cylindrical scales, no medulla, 

 and are striate, due to the fibrous cells. 



The roots and bulbs are not present for the wool is not plucked but 

 shorn. Only the so-called Tanners' wool, which is obtained by treating 

 the skin with slaked lime, and skin wool, and sterblijig' s wolle, dead 

 wools which are obtained from drawn-off hides, and from deceased animals 

 by pulling out the hairs, show the presence of bulbs which are easily rec- 

 ognized by their light color and oval form. 



Wool which was removed from the hide by means of lime is recognized 

 by its brittleness, microscopically by its lack of oil, and is filled with air. 



Sheep's wool is usually always white, seldom gray-brown to black. In 



