616 THE INTERNAL, SECRETIONS AND IMMUNITY. 



fourth day. The pain, rigidity, and sensitiveness of the abdom- 

 inal wall cannot, therefore, be the result of a local, direct action 

 of the intestinal lesion upon overlying tissues through pressure, 

 contiguity of tissue, etc., but, instead, the incidental expression 

 of a general physiological function of which leucocytosis is an 

 important attribute. 



That this is true is also sustained by the facts that the 

 anatomical subdivisions of the peritoneum are purely arbitrary 

 and that, as far as continuity of tissue goes, we are dealing 

 with a single membrane. Unless the entire peritoneum be in- 

 volved in the inflammatory process, therefore, the plea that 

 the symptoms referred to are due to extension of the latter to 

 its parietal or sensitive portion cannot hold. The cases in 

 which eoeliotomy reveals no signs of peritoneal inflammation 

 notwithstanding the presence of these symptoms; the sudden- 

 ness with which the latter .may develop; the facts that they 

 often appear before perforation has occurred and that the pain 

 sometimes appears here, as in appendicitis, in spots quite re- 

 mote from the area in which the lesion occurs, need only be 

 mentioned to show that such cannot be the case. 



Further evidence that we are dealing with a general proc- 

 ess is afforded by the long list of diseases in which leucocytosis 

 occurs and which includes, as already stated, all inflammatory 

 disorders. Among the tissues which show a special predilection 

 for diseases attended with leucocytosis are the serous mem- 

 branes. Pleurisy, peritonitis, pericarditis, meningitis, etc., are 

 familiar diseases in this connection. All are also accompanied 

 by a more or less copious exudation of serum in which leuco- 

 cytes, fibrin, and products of tissue-proliferation of the endo- 

 thelial and connective-tissue cells prevail. 



When, in the course of typhoid fever, perforation is about 

 to occur, the fact that localized inflammation of the sensitive 

 parietal peritoneum is not always found to account for the 

 presence of leucocytes does not preclude the possibility of sud- 

 denly developed cellular overactivity manifested by enhanced 

 cellular metabolism. Under these circumstances the sensitive 

 parietal layer would be as markedly involved as the visceral. 

 The pain and superficial tenderness would thus appear not- 

 withstanding the total absence of sensation possessed by deeper 



