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CHAPTER V. 



MODES OF ORIGIN OF REPRODUCTIVE UNITS AND OF CELLS. 



Modes of origin of reproductive units. Development of ' zoospores ' in 

 Conferva cerea. Evolution of ciliated spore in Vaucherla. Forma- 

 tion of * resting spore ' in (Edogonium. Development of spores 

 in Achlya prolifera; rapidity of process. Similar mode of for- 

 mation in other Fungi, and in Lichens. Mode of origin of Nuclei, 

 Formation of Cells within the internodes of Characece, Develop- 

 ment of ovule, and of endosperm cells, in Flowering Plants. 

 Mode of origin of germs in Protomyxa, and in higher Amcebse, 

 Formation of ova in lower Animals. No doubt about mode of 

 formation of yelk-mass and vitelline membrane in Nematoids. Mode 

 of origin of ova in higher Animals. Origin of Spermatozoa, 

 antherozoids, and pollen grains. 



Above evidence shows that independent Living Units are at first form- 

 less. The Cell a product of Evolution. Non-essential nature of 

 nucleus and cell-wall. Virchow's hypothesis untenable. Most 

 necessary to consider properties of Living Matter. 



Origin of Living Units, as specks of protoplasm, in blastemata. Ex- 

 periments of Onimus. Observations on mode of origin of white 

 blood corpuscles. Another mode in which Cells originate. Five 

 fundamental modes by which independent Living Units are 

 produced. Can a fluid live? Comparison between the Growth 

 and Genesis of Living Matter. Theoretical indications not adverse 

 to Archebiosis. 



THE mere form^ therefore, of living things, or of 

 the active elemental parts of higher organisms, 

 has lost its importance. Vital manifestations are now 

 known not to be dependent upon visible organization 

 of any kind ; they are the results of peculiar molecular 



