14 The Unity of the Organism 



formation, or something else. Any such suspicion is, how- 

 ever, completely done away with by the fact that much the 

 same type of spermogenesis is known to occur in other ticks. 

 Casteel cites particularly the observations of Katharine 

 Samson on the development of the sperm of Ixodes ricinus 

 and Ornithodes mouhata as furnishing cases to which that 

 of Argas is "in many respects parallel." 



After all that has been said in the previous pages, it is 

 almost needless to point out the significance for our general 

 contention of this remarkable case of spermogenesis. Were 

 we living in that comfortable era of life-philosophy wherein 

 theologians studied nature for the purpose of proving that 

 everything in it was made to meet some human need, we 

 could easily recognize this case as one designed expressly 

 to assist man in refuting the false dogma of Chromatinic 

 Omnipotence in heredity. 



It is hard to imagine a developmental process in which 

 denial of form-determining power to non-chromatinic, even 

 non-nuclear parts of the cell would be a greater folly than 

 would be the denial of cytoplasmic "form-determination" 

 in the production of the striated layer of the spermatid, or 

 of the growth of the outer tube, or of the inner tube, or 

 of the turning inside-out of the outer tube. In fact, by far 

 the greater part of the astonishing transformations here 

 gone through are cytoplasmic, the nuclear changes being 

 relatively slight. 



It may be worth while to remind the reader again, so 

 boldly does the real truth about hereditary substance stand 

 out in this case, that the cardinal evil in the chromatin 

 dogma is that it implies the denial of great masses of the 

 most direct observational evidence we have as to what the 

 physical bases of heredity may be, and so tends to detract 

 attention from them. We may predict that the important 

 research which has made known this unique case of organic 

 genesis will pass almost unnoticed by the geneticists of our 



