DERMOID SYSTEM. 297 



vital forces are feeblest, it is under those circumstances 

 that the skin is most susceptible of the action of these 

 poisons. 



Q. How are the cutaneous absorptions from which dis- 

 eases arise to be divided ? 



Jl. Into those which act through the cuticle, as the 

 itch, herpes, tinea, and the pestilential diseases; and into 

 those which require the removal of the cuticle, as the vac- 

 cine, variola, hydrophobia, the bite of the viper. 



Q. Where do the cutaneous exhalents arise? 



A. From the external capillary system which surrounds 

 the chorion and embraces the papillae. 



Q. What proves the existence of exhalents ? 



/?. It is proved by the injections which are poured out 

 on the skin, and the sanguineous exhalation in the form 

 of bloody sweating. 



Q. To what cause are many winter coughs to be as- 

 cribed ? 



#. To irritating matters, which in pulmonary transpi- 

 ration are lodged in the lungs; and this accounts for coughs 

 which are irritating without increased mucous effusion. 



Q. Where are the cutaneous exhalents most abundant? 



<fl. In the face and chest, where sweating is most pro- 

 fuse. 



Q. What effect has season on cutaneous transpiration ? 



#. It is most abundant in summer. In winter the pul- 

 monary exhalation and urinary secretion act vicariously. 



Q. Whence is the source of the oily fluid which is 

 thrown out on the skin? 



t/?. It is an oily exhalation, such as that of fat which 

 takes place in the cellular tissue. Bichat has never been 

 able to discover sebaceous glands. 

 38 



