THE JOURNAL OF PHARMACOLOGY. 189 



Animal Wools and Hairs.^' 



By Smith Ei.y Jei.i.iffe, M.D., Ph.D., and Ernestine Molwitz, Phar.D. 



Contribution from the Microscopical Laboratory, of the College of 

 Pharmacy of the City of New York. 



The hairs of the higher animals are cylindrical or conical, horny struc- 

 tures, growing singly or in groups and having their origin in a follicle in 

 the skin. At the end of the hair is a bulbous enlargement which rests 

 upon a papilla situated at the base of the follicle. 



The skin is composed of two layers : the inner layer, cutis, consisting 

 of connective tissue chiefly made up of a mucilaginous substance, and the 

 outer layer, epidermis, which consists of horn cells (also some mucous 

 cells which eventually become horny) and as the hairs consist entirely of 

 horn cells they may therefore be regarded as part or filiform continuations 

 of the epidermis. 



Hair structures vary greatly for they are found in all their different 

 stages (of transition) in nature, from the finest wool to the stiff quills of a 

 porcupine, and are classified as grannen hairs (beard hairs), and stichel 

 hairs (bristly hairs). The differences existing in their categories are 

 caused less by their anatomical resemblance than by their external prop- 

 erties of firmness, stiffness, breadth, length, etc. 



In order to make this more clear, one notices that at their lower 

 end the grannen hairs on a rabbit's skin cannot be distinguished from the 

 wool hairs around it, whereas the tips have the same structure as the 

 stitchel hairs ; also that the wool hairs of rabbits, beavers and many other 

 fur-bearing animals show the same typical construction as the real gran- 

 nen hairs of the domestic sheep. 



For this reason the different sorts of hairs are determined more readily 

 by their external appearance. 



The wool hairs are fine, soft and curly. The grannen hairs at the ex- 

 treme third are more straight and stiff, pointed, usually thick and darker 

 than the wool hairs of the same animal and moreover larger than the lat- 

 ter. Grannen hairs and wool hairs together constitute the fleece. Stichel 

 hairs are short and stiff, occurring on less hairy parts of the body of an 

 animal, usually at the extremities— head, etc. Bristles and quills need 

 no further explanation. The former are generally solid and only possess 

 a slightly developed pith, being cylindrical ; whereas the latter are more 

 conical, usually hollow and with an unusually large pith. 



Examining the hair externally, a bulbous enlargement will be noticed 

 at the base, and above this a contracted portion. The greatest width of 

 the hair lies in the extreme third. 



* Translated and arranged from " Der Microskopie der technisch verwendeten 

 Faserstoffe. " By Franz Ritter von Hohnel. 



