1894.] MICROSCOPICAL JOURNAL 313 



the leucocyte was seen again to attach itself to the 

 wall, and use the same process in penetrating it. 



5. The clear protoplasmic process works its way 

 through the wall, and in the channel of protoplasm thus 

 formed, the granular matter rushes through the wall and 

 occupies the clear process which is now outside the ves- 

 sel, and leaves clear the portion of the leucocyte still 

 within the vessel. 



6. This clear portion soon comes through the wall and 

 the leucocyte regains its former shape. 



The thought came to me that perhaps it was the coarsely 

 granular corpuscles, heretofore described, in which the 

 granules are seen to rush from one side of the cell to the 

 other, that were the ones which penetrated the wall, but 

 when I considered the small number of this variety when 

 compared with the finely granular leucocytes, and the 

 large number of leucocytes which so escape, I thought that 

 it probably must be the finely granular which consti- 

 tuted the larger part of the escaped leucocytes. 



Of course, the phenomena observed give rise to many 

 interesting questions, but to me it seems evident that the 

 condition brought about by irritation causes in the leu- 

 cocyte, a certain activity which is manifested by the phe- 

 nomena, and which results in its escape from or rather 

 through the vessel wall. Whether it takes place through 

 the so-called stomata, or through the cement substance 

 between the cells (endothelial) of the vessel wall, I could 

 not determine. 



In conclusion I would say, that although my results 

 differ somewhat in some particulars, from those hereto- 

 fore obtained, still, in the words of Claude Bernard : " In 

 physiological studies we must always carefully note any 

 fact that does not accord with received ideas, for it is al- 

 ways from the examination and discussion of this fact 

 that a discovery will be made if there is one to be made." 

 Read at the Brooklyn meeting of the A7/ier. Micr. Society. 



