IO DEFENSIVE FERMENTS OF THE ANIMAL ORGANISM 



necessary for each separate organism, paying due 

 attention to other nutritious materials and conditions, 

 \vill no doubt lead to exact methods for the culture of 

 separate cells in the laboratory. Following this 

 line of inquiry we could surround certain micro- 

 organisms with peptones whose composition we are 

 familiar with, and so acquire a deeper insight into 

 the processes of their metabolism. 2 Even the mode 

 of decomposition of the substrate, and of the inter- 

 mediate stages, may furnish some important hints as 

 to the specific functions of the cell and, in many 

 cases, allow us to recognize particular organisms. 2 ' 2 

 We shall, by this means, understand why certain 

 germs thrive upon certain media, while on any other 

 substrate they either cease to grow or perish entirely. 



It will also be possible to determine exactly, which 

 of the decomposites and by-products formed from the 

 culture medium produce harmful effects. 



There is no doubt that, in the organic world, cer- 

 tain species prepare the soil for others, and in this way 

 one organism acts as a pioneer to the others. It is a 

 most interesting task to follow up this co-operation 

 of different living beings in all its details. To a 

 certain degree we have, in the co-operation of single 



If the nitrogenous basis from which different micro- 

 organisms obtain their nourishment is not known, it might 

 be possible to obtain a culture medium by decomposition of 

 the micro-organisms themselves. 



2 a A firm at Hochst a/M. supplies peptones of definite 

 composition for this purpose. 



