Organisms from Eggs 149 



of yeast can be caused by the press juice from yeast; 

 or characteristic oxidations can be induced by the 

 ground pulp of organs. The question arises as to how 

 far the divisibility of living matter can be carried with- 

 out interfering with the total of its functions. Are 

 the smallest particles of living matter which still exhibit 

 all its functions of the order of magnitude of molecules 

 and atoms, or are they of a different order? The first 

 step toward obtaining an answer to this question was 

 taken by Moritz Nussbaum, 1 who found that if an 

 infusorian be divided into two pieces, one with and 

 one without a nucleus, only the piece with a nucleus 

 will continue to live and perform all the functions of 

 self-preservation and development which are character- 

 istic of living organisms. This shows that at least two 

 different structural elements, nucleus and cytoplasm, 

 are needed for life. We can understand to a certain 

 extent from this why an organ after being reduced to 

 a pulp, in which the differentiation into nucleus and 

 protoplasm is definitely and permanently lost, is unable 

 to accomplish all its functions. 2 



The observations of Nussbaum and those who re- 

 peated his experiments showed that although two differ- 

 ent structures are required, not the whole mass of an 



1 Nussbaum, M., Arch. f. mikroscop. Anat., 1886, xxvi., 485. 



3 It must not be overlooked that in bacteria and the blue algae no 

 distinct differentiation into nucleus and protoplasm can be shown. To 

 these organisms, therefore, the experiments of Nussbaum cannot be 

 applied. 



