70 



Loeb-^*''). who showed lh;il Ihc duralion ol' hfc of sou- 

 urchin eggs, Ic'rliUzcd ;md iiiiroiiilizod. ai'c inrhienccd by 

 the lemperalure. Still l)rlU'i- are llie ex|)ci*inienls ol' Loch 

 and N () r I h r o [) "•■'* with Ihc I'luit I'ly (lroso|)hila, (he 

 hi'c ol' which as funclion of lemperalure runs as a mono- 

 moleeidar reaction. Witliin a ccrlaiii limit of teui|)cralurc, 

 the temperature eoelTicicnt is 2. i. e.. that at an increase in 

 temperature of 10 C llic duration of life is only lialf as 

 long. 



It can be seen, that the mechanistic apprehensions of 

 the various life i)rocesses are the conclusions of clean 

 cut experiments, which show the ultimate continuity between 

 the living matter and the non living world. 



Plven if it, at the present time, looks as if growth j)romot- 

 ing substances for the tissue cells cannot be found as 

 definite substances, we are not allowed to give up the 

 hope, that such substances exist. To day, we are working 

 wdtli many different substances of which we have no know- 

 ledge whatever. So much has been accomplished in immu- 

 nology, in spite of the fact, that the reacting substances 

 are not yet known or isolated. Also the vitamines and the 

 hormones we do not know at all in pure condition. 



Not many years ago it w^as believed that a solution of 

 sodium chloride was a physiological solution, as soon as 

 it was isotonic. To day we know that a isotonic sodium 

 cloi'ide solution is not sufficient to |)r()lccl li\ing cells. J. 

 Loeb 3*''9) has shown, that a pure solution of sodium cloridc 

 is toxic for the cells and that this toxicity can be neu- 

 tralized by bivalent or still better b}^ trivalent ions, such 

 as Ca+-i- and Mg+++ when added to the NaCl solution in 

 a proi)er quantity, and that also K^- is imjiortant for main- 

 taining life. Loeb explained this phenomenon by stating 

 that \a, K and (^a ions ai-c combined with cL-rlain colloidal 

 substances within the cells. These combinations in certain 

 proportions in the cells are necessary for the normal vital 

 processes. If one places the cells in pure NaCl solutions, 



