REPRODUCTION. 68 1 



isation, so that each succeeding generation represents an 

 advance, though it may be a slight one, on its predecessors. 

 The advance may not be at all perceptible for many gene- 

 rations, but then a new and distinctly more highly organised 

 form appears, as in cases of what is termed saltatory evo- 

 lution. Naegeli conceives the matter in this way, that the 

 idioplasm of every organism tends to become more and more 

 complex ; that is, to become more and more completely 

 differentiated physiologically and therefore also morpho- 

 logically. On this view we can readily understand how that, 

 step by step, there have sprung from simply organised plants 

 others of increasingly complex organisation. Evolution is no 

 longer a matter of chance, but is 4he inevitable outcome of a 

 fundamental property of living matter. 



BIBLIOGRAPHY. 



Strasburger ; Theorie der Zeugung, Jena, 1884, p. 96 : also, Die Con- 

 troversen der indirecten Kerntheilung, Bonn, 1884, p. 27 (Archiv 

 fur mikroskopische Anatomic, Vol. xxill). 



Dodel-Port ; Biologische Fragmente, II, 1885. 



Belajeff ; Bot. Zeitg., 1885. 



Strasburger ; loc. cit. 



de Bary ; Die Familie der Conjugaten, Leipzig, 1858. 



Strasburger ; loc. cit. 



Lubbock ; British Wild Flowers in their relation to Insects, 1875. 



Darwin ; Forms of Flowers, 1877. 



Darwin ; Cross- and Self-fertilisation of Plants, 1876. 



Darwin ; Variation of Animals and Plants under Domestication, 

 2nd ed., 1875, Vol. n, p. 45. 



Gartner ; Versuche und Beobachtungen iiber die Bastarderzeugung, 



1849, p. 45 5- 



Darwin ; Variation, Vol. I, p. 413 (Graft-hybrids). 

 Darwin ; Variation, Vol. I, p. 460. 

 Darwin ; Variation, Vol. II, p. 349. 

 Brooks ; The Law of Heredity, Baltimore, 1883. 

 Naegeli ; Mechanisch-physiologische Theorie der Abstammungs- 



lehre, 1884. 

 Strasburger ; loc. cit. 



