100 



As the bulb contracts into the hair, these gradually become consoli- 

 dated, and form either a cellular medulla, by the absorption of the nuclei 

 and cell walls, or a tolerably solid medulla, by the agglutination of the 

 whole structure into one. 



The bulb may be said to terminate where the hair enters the epithelial 

 eheath and receives its scaly coating. 



These appearances are most marked in the large whiskers of the cat 

 and other animals. In many instances, T have detected a second bulb 

 below the first, but the appearance is not common ; it might arise 

 either from preternatural constriction of the upper part by the fibrous 

 sheath, or from the development of a new hair, prior to the old one being 

 shed, or from disease. 



Hairs in many situations are abundantly provided with oil glands ; in 

 others they ai'e more rare. Where these exist, they are two in number 

 for every hair, and are situated on opposite sides of the follicle, a little 

 above the commencement of the horny sheath. According to their 

 number and activity in secretion, we have either a dry and harsh, or 

 a moist and oily hair. 



In many of the lower animals, these are far more abundant than with 

 us — no single hair being without them. The structure of these glands 

 is very simple, being nothing more than a convoluted and distended tube. 



A German author says, that nine hairs out of ten in the majority of 

 persons, have a small entozoon, a kind of acarus, close to their roots, and 

 this he looks on as so constant an occuri'ence, that he considers it an ex- 

 ception for the follicle to be free from it. He has even found it in the 

 foetus. I have never yet met with such an object. Mr. E. Wilson has 

 figured a similar insect. 



The development of the hair in the lower animals, is essentially the 

 same as in man. The peculiarities we meet with are more of degree 

 than of kind, and may be shortly summed up. 



If we examine very closely, in ourselves, any hairy surface, a day or two 

 after it has been shaved, we shall see that the hairs do not arise singly 

 or independantly, but in groups of two or more. These emerge from one 

 aperture, but have independant roots. 



This being the case with us, whose hair is by no means densely 

 planted, we may readily imagine it to attain to a still greater extent when 

 the hair is more abundant. 



I have as yet only examined the dog, the sheep, the pig and cow, and the 

 hare. In the hare (lepus timidus), we find it a general rule, that one 

 large hair and fourteen small ones spring from the same spot — the 

 largest being usually implanted the deepest ; the rest iiTegularly round 



