298 UERMOID SYSTEM. 



Q. What is the office of this oily fluid? 



/#. It serves to soften the skin so as to prevent its 

 cracking. 



Q. Why not consider this oil as an exudation of fat 

 through the skin? 



/?. Because, in several parts where there is the least fat, 

 there is the most oil, and vice versa. Besides, physical 

 transudation is denied on vital principles. 



Properties of the Dermoid System. 



1. Properties of Texture. 



Q. What properties of texture are found in the dermoid 

 tissue? 



*tf. Extensibility and contractility to great extent. See 

 this in dropsies, in pregnancy, in tumours. Observe how 

 the skin retracts in a wound. You will find that these pro- 

 perties of texture are manifested in dead bodies. They 

 are not dependent on vital forces, but derive an increase 

 of energy from them. 



Q. When the extension of the gkin is increased, what 

 takes place in the fibres of the dermis, and in the* spaces 

 between them ? 



*#. The fibres are separated, and the spaces increase. 



Q. How is the contraction of the dermoid texture from 

 cold explained? 



/?. The fibres and spaces are much diminished on the 

 inner surface of the chorion; but as the external face of 

 the chorion does not contract in the same degree, a rough- 

 ness is occasioned. 



