PHYSIOLOGY OF MAN, 



CHAPTER I. 



SECRETION IX GENERAL. 



General considerations Relations of the secretions to nutrition General 

 mechanism of secretion Differences between the secretions and fluids 

 containing formed anatomical elements Division of secretions Mechan- 

 ism of the production of the true secretions Mechanism of the production 

 of the excretions Influence of the composition and pressure of the blood 

 upon secretion Influence of the nervous system on secretion Excito- 

 secretory system of nerves General structure of secreting organs Ana- 

 tomical classification of glandular organs Secreting membranes Fol- 

 licular glands Racemose glands Tubular glands Ductless, or blood- 

 glands Classification of the secreted fluids Secretions proper (perma- 

 nent fluids; transitory fluids) Excretions Fluids containing formed 

 anatomical elements. 



THE phenomena classed by physiologists under the 

 head of secretion are intimately connected with the gen- 

 eral process of nutrition. In the sense in which the term 

 secretion is usually received, it embraces most of the pro- 

 cesses in which there is a separation of material from the 

 blood or a formation of a new fluid out of matters fur- 

 nished by the blood. The blood itself, with the lymph 

 and the chyle, are no longer regarded as secretions. These 

 fluids, like the tissues, are permanent constituents of the 

 organism, undergoing those changes only that are neces- 

 sary to their proper regeneration. They are likewise char- 

 acterized by the presence of certain formed anatomical ele- 



