VALUE OF THE ATTRACTION-SPHERE. 329 



spermatocyte of a Salamander, yet they both present an 

 identical modification in the parts of their spheres. Can it 

 also be mere coincidence that these organs have been 

 modified along identical lines in things as widely separated 

 as a Euglypha and the spermatocyte of an Ascaris ? I 

 conceive rather that these facts must foreshadow the 

 appreciation of morphological generalisations, which will 

 embrace such apparently capricious yet similar variation in 

 the spheres at the extreme ends of the organic series, and 

 that it is among the prime objects of progressive cytology to 

 ascertain what these " laws " may be. 



BIBLIOGRAPHY. 



(1) Whitman. The Inadequacy of the Cell Theory of Develop- 



ment. Read, 31st August, at the Zoological Congress of the 

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(2) BUTSCHLI. Protoplasm. Minchin's Trans. 



(3) BUTSCHLI. Ueber die sog. Centralkorper der Zelle und ihre 



Bedeutung. Verhand. d. Nat. Hist. Med. Vet'eins zu Heidel- 

 berg, N.F., bd. iv., heft 5, 1891. 



(4) BUTSCHLI, Weitere. Mittheilungen iiber die Structure des 



Protoplasma. Verhand. d. Nat. Hist. Med. Vereins zu Heidel- 

 berg, N.F., bd. iv., heft 4, Sitzg. vii., Juli, 1894. 



(5) FOL. Jenaische ZeitscJirift fur Medicin, p. 471, 1872. 



(6) FOL. Le Quadrille des Centres, un Episode Nouveau dans 



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(7) BENEDEN, E. VAN. Bull. Acad. Roy., Belg, ser. 3, t. xiv., 



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(8) Heidenhain, Martin. Neue Untersuchungen liber die 



Centralkorper und ihre Bezeihungen zum Kern- und Zellen- 

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(9) BOVERI. Zellen Studien. fenaisclie Zeitschrift fur Medicin, 



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(10) VEJDOVSKY. Bemerkungen zur Mittheilung H. Fol's Con- 



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