224 THE PHYSIOLOGY OF REPRODUCTION 



Loeb's general conclusion is that the phenomenon of fertiUsa- 

 tion (as studied in the sea-urchin, the star-fish, Lottia, Polynoe 

 and Sipunculids) consists essentially, firstly, in a liquefaction 

 or hydrolysis (or both) of certain fatty compounds in the ovum, 

 and secondly, in an initiation in the right direction of a new 

 process of oxidation.^ These changes which occur in the 

 fertilised egg lead to the synthesis of nuclein material from the 

 protoplasm. According to this view, the process of astrosphere 

 formation is not the direct effect of the act of fertilisation, but 

 is a secondary consequence of the new chemical changes which 

 are brought about by the entrance of the spermatozoon.^ 



Delage,^ however, has recently adduced experimental 

 evidence, some of which is opposed to Loeb's interpretation 

 of the observed phenomena. This investigator has shown that 



ansesthetisation with carbon dioxide during maturation) ; and 0. R. dc V Acad, 

 des Sciences, vol. cxli., 1906 (describing fertilisation with various salt solu- 

 tions) ; Treadwell, "Notes on the Nature of Artificial Parthenogenesis in the 

 Egg of Patella obscura, Biol. Bull., vol. iii., 1902 ; Scott, " Morphology of the 

 Parthenogenetic Development of Amphitrite," Jour, of Exper. Zool., vol. iii., 

 1906 ; Lefevre, " Artificial Parthenogenesis in Thalassema mellita," Jour, of 

 Exper. Zool., vol. iv., 1907 ; Kostaneoki, " Zur Morphologic der kiinstlichen 

 parthenogenetischen Entwicklung bei Mactra," Arch. f. Mikr. Anat., 

 vol. Ixxii., 1908. See also Mathews, whose paper has been already referred 

 to (Chapter IV. p. 134, " A Contribution to the Chemistry of Cell Division, 

 Maturation, and Fertilisation,'' Amer. Jour, of Phys., vol. xviii., 1907). This 

 author lays stress on the part played by the centriole, and suggests " that the 

 various methods employed to produce artificial parthenogenesis do not do so 

 by their direct physical action on the cell, but indirectly by producing in one 

 way or another active centriole substance in the cell cytoplasm, or by causing 

 its discharge from the nucleus." 



' Loeb, " The Chemical Character of the Process of Fertilisation and its 

 bearing upon the Theory of Life Phenomena." — Address before the Interna- 

 tional Congress of Zoologists, Boston, 1907, Univ. of California Publications, 

 vol. iii., 1907. 



' Since this was written, Loeb has elaborated his theory further in an 

 important work recently published, in which full references are given 

 ( Die chemische Entwicklungserregung des tierischen Eies, Berlin, 1909). Membrane 

 formation is regarded as an essential factor in normal fertilisation, and 

 is of the nature of a cytolysis of the egg, for all cytolytic agents produce 

 it. Normally the fertilisation membrane is brought about by a lysin carried 

 in by the sperm, which also carries another substance that serves to coun- 

 teract the evil effects of membrane formation. See p. 301, Chapter VIII., 

 where the subject is discussed further. 



' Delage, " Les Vrais Faoteurs de la Parth^nogenese Experimentale," 

 Aroh. de Zool. Exper. et Qen., vol. vii., 1908. 



