Evidence from Profozonn.s 



371 



ing witli the nuclear a))]):iratii.s. Tlie elastic axis, arising from 

 the blepliaroi)last, can he regarded as a forni-dctrrniiiiing cle- 

 ment of endoplasmic origin, the sheath as an ectoplasmie motor 

 substance." * 



As this statement illustrates both the factual ))oiut with 

 which we are concerned and the i)erverting influence of clcnH-n- 

 talist theory on sup]iosedly straightforward descri))tion, let us 

 examine it. If a flagellum is composed of a core cueloscd in 



%. 



c.p. 



\--ax. 



FIGURE 20. FI,At;i:i,l.l'.-M OK KeOI.KXA (aFTEH Ht'TSCIIM ) . 



ax., axial filament, c.p., contractile jirotoplasin (Mnclopin;^ tlu' axial 

 lilanient. e.])., end ])iecc of the flagelluni. r., root of the flagrlluni 

 passing into the body. 



a sheath^ what justification is there for saying that the org.ui 

 arises from a basal granule? According to the clear inipliea- 

 tion contained in the latter part of the statement, only the axial 

 core arises from this source. And if the statement be correct, 

 as it undoubtedly is. th;it the sheath is ectoplasmie, what occasion 

 is there for throwing into the definition tiit- |)urely hypothetical 

 notion that the clastic axis is a "form-dcttrminiug thinent".^ 

 In view of the fact that there is as nnich observational ground 

 for sui)posing the sheath to be "form-detern)ining" as there is 

 for supposing the axial core to be so, either both parts shouhj 



