CYTOMORPHOSIS IN BACTERIA 145 



the cytomorphosis which occurs in multicellular organisms; that 

 with increasing age in protozoa a change in the nucleo-protoplasmic 

 ratio would be found comparable with that which occurs in differen- 

 tiating animal and plant cells. While I am not conversant with 

 the literature, I do not know that this has been done, that is that 

 the life cycles in protozoa have actually been studied as a cytomor- 

 phosis, and that any attempt has been made to trace in them a develop- 

 ment of the same laws which govern the cell changes in the multicellu- 

 lar organism ; but I believe that in the data which have been presented 

 in the preceding chapters of this book there is ample evidence that 

 the cell changes exhibited by bacteria are of this nature, and that 

 this term "cytomorphosis," with the present state of our knowl- 

 edge at least, more clearly explains the nature of the variations in 

 cell structure which are observed, than does the term "life cycle," 

 since it does not necessarily involve any idea of multiplicity in forms 

 of reproduction, and particularly of alternating sexual and non-sexual 

 phases which generally is implied in the term "life cycle." 



My conclusion that the cell changes occurring in cultures of 

 bacteria are a cytomorphosis of the same kind as that exhibited 

 by the cells of a multicellular organism is arrived at only by analogy. 

 No one can state definitely that the growth and cytomorphosis of 

 a population is governed by laws identical with those which govern 

 the growth and cytomorphosis of a multicellular plant or animal 

 until it has been discovered what those laws are. But the pheno- 

 mena so exactly parallel each other, no matter from what angle they 

 are viewed, the analogy is so perfect, that we are justified in 

 excepting this theory as at least a working hypothesis for further in- 

 vestigation. 



The acceptance of this theory demands the acceptance of certain 

 corollaries. If it be granted that the cells of bacteria undergo a 

 metamorphosis of the same kind as that exhibited by multicellular 

 organisms, then it must be granted that to this degree a population 

 of free one-celled organisms, even though those cells have no connec- 

 tion other than the common nutrient fluid which bathes them, be- 

 haves like an individual. There has already been accumulated a 

 great deal of evidence of other kinds to support the idea that there 

 is no essential difference, that there can be drawn no hard and 



