and Experiments on Pus. gn 
action of the secreting surface. In different cases, however, 
the proportion of impregnating saline substances to one 
another is liable to vary, especially that of phosphate of lime ; 
hence, though rarely, calculi occur of this substance in the 
cavity of the abscess.* Hence too the exsiccated pus is liable 
to become soft and moist, from the proportion of neutralized 
potash being greater than usual ; and even deliquescence 
sometimes occurs of the exsiccated limpid fluid. 
1 2. That the same organs, according to their different states, 
secrete from the blood merely water impregnated with the 
saline substances of the serum of blood ; also this fluid 
containing various proportions of coagulable matter like that 
of serum of blood ; and serous fluid with self-coagulable 
lymph, which affords curdy masses : likewise this serous fluid* 
together with this matter which coagulates of itself after 
secretion, highly impregnated with invisibly small particles, 
in such a state of aggregation, as to constitute the thick opaque 
fluid called pus — which states of the secretory organs are 
generally attended with inflammatory action, but frequently 
also without any symptoms of such action. 
13. That besides the consistence of pus depending upon 
the proportion of serous limpid liquid, and opaque matter, it 
also probably depends upon the mode and state of coagulation 
of the matter which affords this opaque part ; analogously to 
the different states of consistence of the coagulated blood 
* On examining the lungs of a patient who died of pulmonary consumption, con- 
cretions were found in a large vomica from the size of mustard seed to a pepper corn, 
which Dr. E. N. Bancroft reserved for my enquiry. I found fhey consisted chiefly 
of phosphate of lime with an unusually small proportion of animal matter. In another 
patient of Dr. Nevinson, matter was coughed up, consisting chiefly of phosphate 
of lime and animal matter, nearly one of the former to three of the latter. 
S S 2 
