146 EXUDATIONS. 



ducing plasticity, although these, like the former, would appear 

 from the results of our investigations to derive their original 

 source from the blood-corpuscles. To assert that the plasticity of 

 an exudation depends solely upon the presence of the phosphates, 

 would be no less unsuitable or uncalled for, than to assume that 

 transudations owe their origin exclusively to a large amount of 

 water in the blood. We have already shown, under the head of 

 fs Transudations/ 3 the untenable nature of such a view, and we 

 would here only remark that the blood of tuberculous, chlorotic, 

 and hysterical patients is often found to be far more watery, with- 

 out, however, transudations having taken place, than the blood of 

 patients having dropsical accumulations in different cavities. We 

 have already instanced amongst the conditions which favour the 

 formation of a transudation, the amount of the lateral pressure 

 exerted by the blood on the walls of the capillaries, the rapidity of 

 the blood-current, the coefficient of elasticity of the walls, and 

 many chemical relations. We cannot, however, venture here, any 

 more than in the involved phenomena of vital processes generally, 

 to refer an important process to one single, perhaps accidentally 

 induced condition ; for, in adopting such an unsatisfactory mode 

 of evading a difficulty, we should run the risk of falling into the 

 error which is too common amongst physicians of the present day, 

 of referring the most complicated pathological processes to the 

 merest chimeras, and endeavouring to explain the modus operandi 

 of certain powerful or inefficient remedial agents by clumsy mecha- 

 nical- or chemical hypotheses. 



The purulent and ichor ous exudations show in special cases the 

 same amount of affinity with the albuminous, and in part even 

 with croupous exudations, as do the other exudative processes. 

 In its purest state the purulent exudation generally, however, forms 

 a yellowish, thick fluid, which differs from every other exudation 

 by the considerable amount of corpuscles which are distributed 

 through it with tolerable regularity. 



These corpuscles, which, however, also occur in other places 

 and in other fluids, as, for instance, in the lymph (as lymph- 

 corpuscles), in the blood (as colourless blood-cells), in the mucus 

 of the mucous membranes (as mucus-corpuscles), &c., are, as is 

 well known, vesicles consisting of a cell-membrane, which often 

 appears granular, of viscid hyaline contents, and of a nucleus 

 which adheres to the cell-membrane. These corpuscles may or 

 may not be included under the head of cells, according to the idea 

 entertained of the physiological cell ; and on this account it would 



