2 THE NEW CELL DOCTRINE 



conclusions of wide bearing can be drawn, it becomes desirable 

 to communicate the results to wider circles. The new 

 achievements of biology are significant and claim the interest 

 of all thinkers, and therefore I have decided to attempt to 

 make clear to you some of our fundamental conclusions. My 

 fellow biologists are requested to excuse the mention of much 

 already known to them. 



The general conclusions of biology are formed slowly. 

 The phenomena of life are so complicated that they can be 

 analyzed only by the most many-sided investigations. If 

 one wishes completely to master the science one would have to 

 be not only a biologist in the stricter sense, but also a chemist, 

 a physicist and a geologist. It has become impossible for a 

 single investigator of our time to acquire special knowledge 

 in the whole field of biology, and you will certainly not expect 

 from me that I attempt to make clear to you all the funda- 

 mental conclusions of modern biology. Indeed for this, the 

 time at our disposal would not suffice. Therefore I shall 

 permit myself to treat only such questions as I have found 

 occasion to consider often in the course of my special work. 

 We may arrange the subjects to be discussed in the following 

 order : 



1. The New Cell Doctrine. 



2. Cytomorphosis. 



3. The Doctrine of Immortality. 



4. The Development of Death. 



5. The Determination of Sex. 



6. The Notion of Life. 



You all know something of cells, which have been described 

 often as the units of life. They are small masses of living sub- 

 stance, in each of which lies a smaller body, which is desig- 



