ON ENZYMES AND LIVING CELLS 103 



figures were seen with the chromatin reduced in quantity, and 

 in number of chromosomes. In many cases division with three 

 and four centrosomes was observed. 



In the cells to which acid had been added, no such increase 

 in nuclei was observed, nor nuclear division figures, and in many 

 cases the chromatin appeared to have been acted upon chemically 

 and to have disappeared. 



The experiments illustrate the extreme sensitiveness of the 

 living cell to variations in concentration of the hydroxyl and 

 hydrogen ion, and the importance of a normal reaction of the 

 medium for cell growth and division. 



ACTION OF ANTISEPTICS AND PROTOPLASMIC POISONS 



There is here a great quantitative difference in action upon enzyme 

 and living cell respectively, which probably has for its cause the more 

 complex and highly organised chemical structure of the cell, causing 

 it to enter more readily into combination with the antiseptic. 

 That the difference is a quantitative and not a qualitative one, how- 

 ever, is shown clearly by many experiments which go to prove 

 that many of those substances which affect cells, and either render 

 them inert or permanently destroy them, have in greater con- 

 centration a similar action upon enzymes. Thus alcohol, chloro- 

 form, salicylic acid, carbolic acid, thymol, and sodium fluoride, 

 which were at one time regarded as affecting living cells only 

 and without action upon enzymes, have now been shown by various 

 observers to more or less retard the action of enzymes also, and 

 to destroy them in greater concentration, although the action 

 varies in degree in different instances and is always less than that 

 upon the cell. The greater degree of action of such substances 

 upon cells has been often taken advantage of as an experimental 

 aid in observing the nature and products of reaction of enzymes, 

 especially of those proteoclastic enzymes which act in an alkaline 

 medium. For such substances stop the growth of the putre- 

 factive bacteria at a concentration in which they have little action 

 upon enzymes. This experimental use of antiseptic agents was 

 first made by Kiihne in studying the products of action of trypsin. 

 In choosing such an antiseptic, one ought to be selected which 

 possesses a strong action upon cells, but as little as possible upon 



