90 LABORATORY METHODS OP 



gland. There is only one fiber to each hair. The 

 shedding -of the hair is a difficult subject to under- 

 stand, but the theory is that the cells in the papillae 

 harden and therefore the hair loosens and falls out. 

 These are called bulb hairs. The papillary hairs are 

 shed in this way from the external root sheath there 

 arises a bud, which grows downward and develops 

 into a new hair, which gradually pushes the old hair 

 out. The condition called goose flesh is caused by a 

 contraction of the muscles of the hair. The nerves 

 supplying the muscles of the hair are derived from the 

 sympathetic nerves and are called pilomotor nerves. 



TH MAMMARY GLANDS. 



These glands are included in the cutaneous glands. 

 They are a variety of compound saccular glands, and 

 are histologically considered as a tube being lined with 

 a basement membrane and glandular epithelial cells 

 with large nuclei. The opening in the gland is called 

 acinus. The end of the tube is called the duct. A 

 large number of these glands is put together and forms 

 a lobule having a small amount of white fibrous and 

 connective tissue placed around it. A large num- 

 ber of these lobules is put together and forms a lobe. 

 The gland, as we see it, is a number of glands i. e., 

 just as the liver is composed of separate livers, so is 



