146 ORGANISED FLUIDS. 



Lastly, Gruithuisen indicated, in solutions of pus and 

 mucus in water, certain animalculae ; those generated in 

 the former being different from those formed in the latter 

 solution. By means of these he asserted that pus might always 

 be known from mucus ; but the infusoria described by him 

 are not confined to the fluids in question, but are such as are 

 formed almost indifferently in any solution of animal matter. 

 It would appear, then, that up to the present time no satis- 

 factory and direct means of distinguishing pus from mucus 

 have been detected, and this for the reason assigned, that the 

 two fluids are essentially identical. 



DISTINCTIONS BETWEEN CERTAIN FORMS OF MUCUS 

 AND PUS. 



Although it is impossible to discriminate between true 

 mucus and pus by means of the microscope in a positive 

 manner, we are yet enabled to distinguish with that instru- 

 ment false mucus from pus, because in this mucus the cor- 

 puscles exist in their fully developed form of tessilate epithe- 

 lium ; now this power of discrimination is not without im- 

 portance, as will be perceived immediately. 



Many persons on arising in the morning are in the habit 

 of expectorating more or less of a substance bearing much 

 resemblance to pus. This habitual occurrence is not un- 

 frequently a source of much uneasiness, not merely to the 

 person the subject of it, but also to his medical adviser whom 

 he is led to consult upon it. 



Now, in such cases as these it is often in our power to 

 dispel the anxiety of our patient and our own at the same 

 time ; for the solid constituents of such sputa are frequently 

 found to consist almost entirely of epithelial cells, in which 

 case we may safely pronounce that they are not purulent ; 

 if, on the contrary, the sputa contain only globules, the evi- 

 dence which this fact would furnish, although apparently, 

 and indeed most probably, unfavourable, would still be but of 

 a doubtful nature. 



