PUS. 155 



heating, a gelatinous mass almost insoluble in water. This sub- 

 stance, which was formerly believed to be the matrix of the 

 nucleoli, and held to be a special material allied to horny sub- 

 stance (keratin), has been as yet found to present no differences 

 from the strongly basic albuminates of potash, to one of which we 

 have already referred in vol. i., p. 333. Other protein-bodies, 

 moreover, besides albumen, enter into similar gelatinous com- 

 binations with potash, and, like them, do not very readily dissolve 

 in water. A great number of the substances which have been 

 pronounced to be keratin, are nothing more than compounds of 

 strongly alkaline bases with protein-bodies. 



In the experiments on pus made by Messerschmidt and myself, 

 to which I have already referred, we were lead from certain re- 

 actions to the erroneous conclusion, that we had been able to 

 distinguish several varieties of fibrin in the capsule, nuclei, and 

 nucleoli, an error which, unfortunately, met with more general 

 approval than it deserved, considering the state of science at the 

 time. We believe that we have now shown that there are not 

 sufficient grounds for regarding any constituents of the pus-corpus- 

 cles as identical with fibrin, and we need scarcely repeat the remark 

 we have so often made, that it is injurious to the cause of science 

 to attempt to identify or name different substances without having 

 had the power of closely investigating them. A deficiency in our 

 knowledge is in such a case very far preferable to the mere 

 accumulation of vague hypotheses. 



We have already shown from direct observation (vol. i, p. 252) 

 that fat is accumulated in the corpuscles of the pus. 



We are, unfortunately, still deficient in observations which 

 would enable us to judge of the quantity of salts contained in the 

 pus- corpuscles when compared with the amount present in its 

 serum. 



We now proceed to consider the constituents of the serum of 

 the pus. This fluid, when we can succeed in skimming it from the 

 corpuscles, which only sink very slowly, is found to be entirely 

 colourless, or of a faint yellow colour, and perfectly clear; it rarely 

 contains fat-globules ; it has a faintly alkaline reaction, and coagu- 

 lates on being heated, most frequently into flakes, but sometimes 

 in the form of a dense white mass. Acetic acid occasionally ren- 

 ders it strongly turbid. 



The albumen of the intercellular fluid of the pus does not differ 

 from that of the blood ; at all events, all its reactions correspond 

 perfectly with those of ordinary albumen. Moreover, the quantity 



