06 



in the hair of different animals, to enable us, from an examination of 

 them, to distinguish the source from which they sprung. Mr. Busk 

 called attention to this subject some time ago, and showed the peculiarity 

 of certain classes, such as the bat tribe, the deer, the roebuck, and others. 

 1 can only say from my own experience, that I have been unable to draw 

 any general rule. All that I can say is, that certain hairs are peculiar 

 to certain tribes, e, g. the porcupine's, peccary's, the hare's and rat's, 

 the shrew's, ornithorynchus', the bat's and racoon's, the deer's, and the 

 sheep's and goat's ; and, as I have before mentioned, the whole tribe of 

 burrowers can be recognized by their fur. 



The description hitherto given has applied solely to that portion of 

 the hair above the skin ; we must now describe the root, and enquire 

 into the growth and development of the hair generally. 



The commonest observer must be aware that a considerable portion of 

 the hair is implanted in the skin ; if the place from which it has been 

 drawn is examined by a magnifying glass, a distinct aperture may be 

 seen — the opening of the hair follicle. A more experienced observer 

 is aware of the fact, that when the epidermis is separated from the true skin 

 by maceration, the hair is brought away likewise. This shows that the 

 hair is not a part of the cutis vera. The same person will probably have 

 seen that the hair passes apparently through the true skin, into the 

 fatty tissue beneath, and will be at some difficulty in reconciling this with 

 his previous observation. These things are readily explained by a re- 

 ference to the microscope. 



Before describing the anatomy of the hair follicle, we must say two or 

 three words about the skin. This is composed of three layers, the cutis 

 vera or true sldn, which is the innermost and thickest, of a fibrous 

 character. The rete mucosurn, which consists of a number of soft rounded 

 cells, varies in thickness according to its locality, and is intei'posed between 

 the scarf-skin and cutis : the outer layer, or epidermis, or scarf-skin, 

 which lies above the rete mucosum — like it, it is composed of cells, 

 which are irregular in shape and size, in consequence of exposure to 

 the atmosphere, friction, pressure, &c. 



The rete mucosum plays an important part in the formation of all 

 those things which are essentially parts of the epidermis — such as corns, 

 nails, hail's, horns, &c. Each hair follicle consists, like the skin, of three 

 parts ; it is, in fact, nothing more than an involution of that organ, and 

 may be compared to the inverted finger of a glove. It will be necessary, 

 therefore, to prevent misconception or confusion, that we understand 

 rightly the change of terms made when passing from a description of 

 the skin to that of the hair follicle : as, by involution of the finger of the 



