46 TRICIIOLOGIA MAMMALIUM; 



suppose that the basis of the coloring matter of all pile is the saint substance differently 

 modified. 



OF THE SHEATH. The cellular tissue, situated within the follicle and enveloping the 

 button and a part of the shaft, at its posterior extremity, is called the "sheath." Accord- 

 ing to Henle, it consists of two layers, between which is a fatty matter. This part is not 

 said to be formed by the sinking down of the dermis, as the follicle is said to be. 



The sheath generally terminates at the epidermis, but may sometimes, in diseased hairs, 

 be seen obtruding upon the shaft of the hair, above the epidermis, as in fig. 51. 



OF THE FOLLICLE OF PILE. The word "follicle," is derived from the Latin "folliculus" 

 (which is a diminutive of "follis," a bag, purse or script,) and therefore means "a little sac." 



In Anatomy it is defined to be "a secreting cavity." (See Diet, of Med. Terms, by 

 Hoblyn.) Prof. Dunglison (in Hum. Phys., 41,) says: "Follicles, or crypts, are secretory 

 organs, shaped like membranous ampullfB, or vesicles, always seated in the substance of 

 one of the outer membranes of the body, the skin, or the mucous surfaces, and secreting 

 a fluid intended to lubricate them." (See also Dung. Med. Diet., title "Crypta.") 



In Botany, "follicle" means a seed-vessel, husk, or cover. " L'envelope membraneuse 

 dans laquelle sont contenue les graines des plantes " (Diet, of the French Academy.) 



There is nothing in its derivation or terminology to prevent us from using this word as 

 we here do, to mean "a little sac, in which the posterior portion of the shaft of pile, 

 with its button, is found, when the pile has come to maturity;" without interfering with 

 the questions whether it is secretory or excretory. 



This part of pile has, sometimes, but very improperly, been called the "bulb;" for that 

 term, (from bulbus,) in Botany, is applied to the solid roots of plants that have many coats 

 or peels; and in Anatomy, it is applied to parts that have the outward shape of bulbous 

 roots. 



The word "root" has sometimes been, by analogy, but very improperly, applied to this 

 part of pile. At other times the button is considered to be the root; as, for example, in 

 Dunglison's Hum. Phys., 103, it is said, that " the roots of the hair are in the form of bulbs, 

 taking their origin in small follicles or open sacs," &c. It would be better to discontinue 

 the use of the word "root" altogether, as regards pile; as it leads, insensibly, to error. 



Where the follicle is found. Professor Dunglison says, that the consideration of the 

 hair belongs, naturally, to that of the skin; and this integument he describes as consisting 

 of four parts, viz: the cuticle, rete mncosum, corpus papillare, and corium. He copies 

 from Wilson's Hum. Anat, 493, a diagram in which all these, with the adipose tissue 

 (which underlays them all) are depicted; wherein there are seen two hairs, the follicle of 

 one is represented as being in the adipose tissue, and the other below it, And that this 

 did not arise from mere inattention in Wilson, we have a right to infer from the circum- 

 stance that in the explanatory notes it is observed, that in regard to these two hairs, enclosed 

 in their follicles, their relative depth in the skin is preserved. 



On the other hand, Cazenave (in Traite des Mai. de cuir chevelu, 1850, p. 41,) describes 

 the follicle as a little sac lodged in the dermis, having beneath it a coniqxie papilla, which is 



