198 The Microscope. 



now I deny the existence of wandering cells, based upon the fact 

 that both protoplasm and basis substance are alive, and al- 

 ternately may be transformed into one another under our very 

 eyes. 



The hasty assertion of Cohnheim that all inflammatory or pus 

 corpuscles in the cornea are emigrated colorless blood corpuscles 

 or leucocytes, must fall to the ground. All the German and 

 American pathologists, who have accepted Cohnheim 's teachings 

 as the standard ones in the doctrine of inflammation, will of 

 course ignore the novel views which completely upset a theory 

 that held sway for nearly twenty-five years. Even their expla- 

 nation of the silver images in inflamed corneae, that the isolated 

 leucocytes adapt themselves by an intervening brown line of 

 cement-substance, is proved to be erroneous. J. H. Mennen has 

 shown that these brown lines are dotted, interrupted, owing to 

 the presence of delicate intercommunications between the inflam- 

 matory corpuscles. This means that the inflamed cornea, al- 

 though largely made up of indifferent or medullary corpuscles, 

 remains a tissue nevertheless, and is able to re-enter its normal 

 condition or become transformed into cicatricial tissue. It is 

 only after the breaking of the interconnecting threads that the 

 inflammatory corpuscles become isolated and now represent pus 

 corpuscles. An abscess in the centre of the cornea is, therefore,, 

 the result of a disintegration of the tissue, and not an accumu- 

 lation of leucocytes. 



Novel doctrines, deserving a rather acute power of observation^ 

 will find approval in a slow way. It is, however, gratifying to 

 learn that in the United States the new views, which are not 

 the worse for having been dubbed " bioplason theory " by my 

 late friend Louis Elsberg, gain ground from year to year. Charles 

 F. Cox, in an excellent presidential address, delivered before the 

 New York Microscopical Society, January 3, 1890, expresses this 

 progress in the following words : 



" I can well remember, as perhaps you also can, the dis- 

 gusted incredulity with which this new doctrine was received, — 

 an incredulity in which, I confess, I then shared. I am not sure 

 that the appearance of a reticulum in the prepared blood-cor- 

 puscle is even yet generally accepted as evidence of a normal 

 structure of the kind claimed by Dr Heitzmann ; but the claim 

 certainly gains support from the fact that vegetable histologists 



