PUS. 141 



pher: this may be inferred from the different manner in 

 which acetic acid acts upon fibrin and pus corpuscles ; thus 

 the former swells up and is rendered soft and friable by its 

 application, while the latter under its influence become 

 smaller, and their contained molecules more distinct. 



Donne dissents from Mandl's view altogether. At page 

 191. of the Cours de Microscopic, M. Donne expresses him- 

 self as follows : " Thus I do not admit that the globules 

 of pus are formed at the expense of the fibrin of the blood ; 

 that they ought to be considered as a sort of precipitate 

 of the fibrinous part of the fluid blood ; and in spite of 

 their analogy of structure and composition with the white 

 globules of the blood, I nevertheless do not admit that they 

 have any thing in common in their origin and in their in- 

 timate nature with these last. I regard the globules of pus 

 as a product of special secretion direct from the pus forming 

 membrane." 



There appears to me to be much of error in the preceding 

 observations : there is doubtless very much in common be- 

 tween the white corpuscles of the blood and pus globules, 

 viz. a common mode of formation and a common function to 

 perform. 



At the same time it must be admitted, with Donne, that 

 the surface or membrane, from which the pus proceeds, is 

 also intimately associated with the development of the pus 

 corpuscles. 



DISTINCTIVE CHARACTEES OF MUCUS AND PUS. 



We have now to ask ourselves the question, which doubt- 

 less many have applied to themselves before, viz. what are 

 the distinctive characters between mucus and pus revealed to 

 us by the microscope, and the satisfactory recognition of 

 which has been deemed to be of so much importance ? 



To this inquiry no sufficient answer has as yet been re- 

 turned : this difficulty the microscope has failed to solve ; and 

 this, in all probability, for the very adequate reason, that 



