LIVING SUBSTANCE 135 



which possesses no nucleus and whose fate is therefore sealed, be 

 observed with the microscope, it can be seen that it passes 

 from its normal behaviour to complete standstill of all its vital 

 phenomena only very gradually. 1 Certain marine species of 

 Rhizopoda, e.g., Orbitolites, are well fitted for this observation; they 

 stretch out through the pores of their calcareous shell clusters of 

 naked non-nucleated protoplasmic threads, or pseudopodia, of 

 considerable length, and by means of them they move, seize food- 

 organisms and digest food. If such a mass of pseudopodia be cut 

 off from an Orbitolites under the microscope, the network of threads 

 first flows together into a roundish droplet, which thereupon 

 immediately stretches out new pseudopodia of the same form as in 

 the uninjured organism, and moves as if in connection with the 

 nucleated body. The new pseudopodia also seize food- organisms, 

 but are not able to digest them. This latter fact is very important, 

 for from it follows the fact that the non-nucleated protoplasmic 

 droplet is not able to manufacture new body-substance. The move- 

 ments of these microscopic bodies continue normal for hours, and 

 their irritability is also maintained. But the pseudopodia are very 

 gradually drawn in, while new ones are no longer protruded, and as 

 a result the mass draws itself more and more into a spherical lump. 

 It cannot yet be said that the protoplasmic mass is dead, for even 

 upon the next day, if the object be observed at intervals of several 

 hours, extremely slow, feeble changes of form can be perceived. 

 Only after several days does the protoplasmic droplet swell up and 

 disintegrate into a loose mass of granules. 



Thus, death does not come to the cell immediately, but is the 

 end-result of a long series of processes which begin with an irrepar- 

 able injury to the normal body, and lead by degrees to a complete 

 cessation of all vital phenomena. Since during the course of this 

 process vital phenomena are still noticeable, while death as a 

 result of the injury is unavoidable, it is advantageous to character- 

 ise by a name the time from the receipt of the fatal injury up to 

 the definitive death as a time of uninterrupted transitions. Ex- 

 tending a conception introduced into pathology by K. H. Schultz 

 and Virchow ('71), I shall term it necrobiosis. 



It is seen, therefore, that is impossible to draw a sharp line 

 between life and death, that life and death are only the two end- 

 results of a long series of changes which run their course success- 

 ively in the organism. But if, after having established this fact, 

 the transition-stages be left out of consideration for the moment 

 and only the two end-results be considered, on the one side, the 

 uninjured living organism and, on the other, the same organism 

 killed and preserved in alcohol by the modern technical methods, 

 a sharp distinction between these two can be recognised in the 

 fact that in the former the life-process goes on undisturbed, as is 



1 Cf. Verworn ('91). 



