GLAND FOLLICLES AND DUCTS. 97 



of the cuticle or of a mucous membrane, for tte 

 former are instruraental in the production of secre- 

 tions possessing very peculiar properties and con- 

 taiuing much water, while the last produces only the 

 dry horny matter which accumulates, or a softer 

 material which, however, by gradual drying, may be 

 converted into the same sort of passive substance. 

 The relationship is however distinctly seen in disease, 

 for there ave conditions under which secreting cells 

 may cease to produce their characteristic secretions, 

 and shrivel up and waste, becoming at last so changed 

 that some of them might easily be mistaken for a 

 very simple form of non-secerning cell structure. 

 While in "inflammation" the bioplasm of all these 

 cells being supplied with an undue proportion of 

 nutrient material, gives origin to a common form of 

 bioplasm — " pus." 



141. Glaud follicles and ducts. — A gland follicle 

 itself, with its included epithelium, is, in the first 

 instance, but a diverticulum from the duct; which 

 duct is but an inflection of the general sm^face. In 

 the formation both of the duct and the gland follicle 

 epithelium is instrumental. Young cells niay grow 

 in a direction from the duct, and multiplying in num- 

 ber may produce a little collection like that seen in 

 the gland follicle, or a long series may result, as in 

 the formation of the tubes of which some glands are 

 constituted. Eventually the permanent epithelium 

 of the secreting part of the gland differs so much in 

 form and action and properties from that of the duct, 

 that, had we not watched the evolution of both, we 

 should not have been inchned to believe in their 

 common origin. 



142. Foriuation of epitlieliuni and fibrous tissue by 

 bioplasm.— At an early period of development no 

 structural differences can be discerned between the 

 formed material produced by those masses of bio- 

 plasm on the surface of the body which are to give 



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