THE MICROSCOPE. 27 



the effect of carbolic acid upon the vitality of cells could be most 

 easily seen. 



He used solutions of varying strength, from ^j^ to ■^^-^. The 

 most extended series of experiments was made upon the frog; and 

 less extended ones upon the blood of the rabbit and man. 



The result of the experiments shows that "carbolic acid in 

 solutions of y^ and over, causes either immediately, or in a short 

 time, cessation of vibration in living ciliated cells, with a rapid^ 

 characteristic disintegration of their protoplasm and death of the 

 cell." 



With solutions of -^^j the ciliary movement ceases in a few 

 seconds, the movements becoming gradually slower and slower. If 

 the movement of the ciliae is languid it is temporarily quickened 

 when the acid is first brought in contact with the cell. As the ciliae 

 cease their motion degenerative changes occur in the protoplasm 

 of the cells. It is resolved into two kinds of material — one clear, 

 transparent and feebly refractive; the other strongly refractive, ap- 

 pearing as shining globules. "The nucleus shrinks, not infrequently 

 exhibiting, as it does so, distinct movements in the intra-nuclear 

 net-work; and especially noteworthy in solutions of this strength is 

 the development in a large number of these cells, within a few 

 minutes, of a wedge-shaped, more or less refractive, sharply outlined 

 net-work, extending from the ciliary border to the nucleus, within 

 which are sometimes seen delicate parallel lines, perpendicular to 

 the free border of the cell. 



This peculiar net-work, lying invariably between the ciliary 

 border and the nucleus and never extending below the latter, would 

 suggest a difference in the structure of the protoplasm in this part 

 of the cell which is not without significance in view of the present 

 uncertainty of our knowledge concerning the relations between the 

 ciliae and the nucleus and the cell body. (Does not the author 

 accept the researches of Klein ? ed.) 



The shining globules tend to coalesce and gather outside the 

 cell body within the first forty-eight hours." 



"In very dilute solutions (^i-g- to -^^Q-f^), carbolic acid may cause 

 if long continued, slight degenerative changes in the protoplasm 

 and the death of the cell; but its most noteworthy action is its 

 inhibitory effect upon ciliary movement. This may be retarded by 

 it, or even entirely checked, without necessarily determining the 



