372 The Unity of the Organism 



be mentioned if a guess about form-determination is to be made, 

 or neither should be. The consensus of view among autliorities 

 that flagella are either ectopLasmic or endoplasmic structures 

 ought to be a sufficient refutation of the speculation that the 

 basal granule, whatev^er its source, is the "form-determiner" of 

 the organs ; but when an erroneous speculation has become an 

 imperative idea, as the chromatin hypothesis seems to have 

 become for some biologists, nothing seems to suffice short of 

 going through the operation of killing it time after time even 

 though it has been dead for many months. 



The truth is that if we speculate about "form-determination" 

 of flagella^ and do so on the basis of the objective evidence, we 

 have to recognize that in some cases neither axial core nor 

 blepharoplast can be the determiner for the sufficient reason 

 that no such structures exist. For example, Patton has shown 

 conclusively that in the species he studied the flagellum arises 

 from the cytoplasm of the cell quite independently of both the 

 nucleus and the blepharoplast. "The flagellum, about 40 in 

 length, consists of a single stout filament which arises from 

 the achromatic space just anterior to the blepharoplast and 

 passes out of the anterior end. The intracellular portion does 

 not differ in structure from the remainder and it has no basal 

 granule in connection with it." ^ The absence of the axial core 

 in this animal is emphasized as follows: "It is important to note 

 that the flagellum under a high magnification consists of a 

 single thick filament and not of a number bound together." ^ 

 This case is especially convincing in that although technical 

 methods were used that are held to be specially trustworthy for 

 differentiating chromatic material, so that the nucleus with its 

 chromosomes and the blepharoplast were brought out sharply 

 against the surrounding faintly stained cytoplasm, the beginning 

 of the flagellum in the less deeply stained part of the cell was 

 clearly recognizable. 



The importance of the main issue here is so great as to 

 justify my repeating what I have said many times. The 

 central question is not whether there may be a granule (or 

 some other substance not made visible by the methods used) 

 which may be form-determining for the flagellum, but 

 whether we shall refuse to accept the observational evidence 

 that the achromatic substance contributes, at least, to the 



