224 Progress of Rational Pathology. 



not re-act from galvanism and mechanical irritants, but con- 

 tracts in cold water, and when dissolved in acetic acid is not 

 precipitated by ferrocyanide of potass. 



d. Serous membranes. — The conditions for the production 

 of the so-named hemorrhagic exsudations of Lannec, are ac- 

 cording to Rokitansky partly general, (as the tubercular dia- 

 thesis) partly local, (at times simple inflammation, or repeated 

 inflammation in some imperfectly organised false membrane, 

 from the imperfect or too delicate structure of the new ves- 

 sels.) This exsudation forms a coagulum, which may be more 

 or less thick and consistent, adherent to the walls of the cavity, 

 rich in colouring matter, or white, within which the red effu- 

 sion is kept fluid. The coagulum changes into a resisting 

 leathery layer, which becomes at most only partially organised : 

 the enclosed fluid grows brown or yellowish, and clear, and its 

 secondary deposits get the consistence of a kind of pulp ; re- 

 absorption is rare : death usually results quickly from exhaus- 

 tion ; in the most favourable cases, after the re-absorption of 

 the fluid, a breaking down of the periphery of the coagulum 

 takes place, inside which is found a rusty-coloured or yellow 

 layer. In the peritoneum haemorrhagic exsudations assume 

 a black and blackish-blue colour from the action of the gas 

 contained in the bowels (Melanosis stratiformis.) Of the so- 

 called milk spots in the heart, Skoda and Kolletschka dis- 

 tinguish two sorts — those on the serous membranes are the 

 effects of pericarditis, the others under them are caused slowly 

 by repeated determination of blood to the part. Paget consi- 

 ders it impossible to determine whether these spots are situated 

 above or below the serous membrane, and considers them to 

 be always the result of inflammation, because adhesions in 

 the form of fine threads between the large vessels are found 

 along with them. Paget considers pericarditis to be a very 

 common disease, for out of 58 bodies he found traces of it in 

 11. He thinks that it often occurs (though overlooked) in 

 many acute diseases, and in typhus. 



