3 i2 SCIENCE PROGRESS. 



Hence, as it seems to me, whilst we can and ought to 

 get rid of the numerical idea expressed by the word unit, we 

 cannot get altogether rid of the idea of individuality, and 

 we must do our best to bring it into harmony with the facts. 



Since there is an inseparable connection between the 

 idea of number and the word unit, we ought to get rid of 

 the expression " unit of life," and use some other term 

 which shall denote alike the simplest and the most com- 

 plex of living beings. The word organism I have aheady 

 objected to because of its double connotation — would it not 

 be better to make use of such a word as "biont," which is 

 as nearly as possible the equivalent of the German " Leben- 

 diges " ? Anything which leads or is capable of leading an 

 independent individual life is a biont. Thus a cell may be 

 a biont, as in the case of the protozoa, or it may be a con- 

 stituent part of a biont, as in the case of the metazoa. In 

 any case the cell is the simplest form of biont known, for if 

 we 2"o behind the cell we have structures which are not 

 capable of leading an independent individual life. 



But a cell in the case of metazoa, or the nucleus and 

 other structures in the case of protozoa, and unicellular 

 plants are things which, whilst they participate in, and con- 

 tribute to life, and to that extent may be considered as living, 

 are not in themselves capable of independent individual 

 existence. They may be called metabionts. 



The terminology suggested may not be perfect, but by 

 the use of it or of something equivalent we may shake our- 

 selves free of the false ideas which have clustered about 

 individual life units, and start with a new hope on an inquiry 

 into the nature and growth of bionts. 



An essential part of our conception of a biont is the 

 union of two substances, cytoplasm and nuclein. It does 

 not matter, for present purposes, that we know nothing 

 exact about these two substances, and still less of the 

 manner in which they operate together to produce the 

 phenomena of life. It suffices that we know that there are 

 bionts whose structure is so simple that we can affirm no- 

 thing more of them than that they consist of cytoplasm and 

 nuclein, e.g., Bacteria, Yeast, Oscillaria, etc. 



