320 DARWINISM TO-DAY. 



it, having been 'improved' by Messrs. Sutton & Sons, is still 

 regarded as 'the best in the trade.' This is definite variation, ac- 

 cording to Darwin's definition, for those weeded out did not differ 

 from the selected, morphologically, except in degree, the variations 

 towards improvement not being quite fast enough to entitle them 

 to survive. 



"M. Carriere raised the radish of cultivation, Raphanus sativus, 

 L., from the wild species R. raphanistum, L., and moreover found 

 that the turnip-rooted form resulted from growing it in a heavy 

 soil, and the long-rooted one in a light soil.* Pliny records the 

 same fact as practised in Greece in his day, saying that the 'male' 

 (turnip form) could be produced from the 'female' (long form), by 

 growing it in 'a cloggy soil.' Both forms are now, of course, 

 hereditary by seed." 



10 Nageli. C. von, "Mechanisch-physiologische Theorie der Ab- 

 stammungslehre," 1884. 



11 Korschinsky, S., "Heterogenesis und Evolution," Naturwiss. 

 Wochcnschrift, Vol. XIV, pp. 273-278, 1899. 



12 Recently, Georg Pfeffer ("Die Entwicklung," 1895) has pro- 

 posed a theory of orthogenetic evolution not very different from 



the much earlier Nagelian one. Pfeffer postulates as 



) ers eory j n ] ieren ^ j n living matter a capacity for change and 

 ol orthogenesis. . 



for self-directing this change. Ihe principle of 



change or progress he calls the conception of "developmental-screw" 

 (Entwicklungsscliraiibe) , and for directing this progress the con- 

 ception of "self-steering" (Selbststeuerung). Both these capacities 

 of individualised living stuff are something over and beyond the 

 mechanical and physico-chemical attributes of living matter. "On 

 the contrary," says Pfeffer, "life consists of the capacity (more 

 exactly the exercise of this capacity) of consciously permitting and 

 consciously influencing (that is, actually producing) through 

 physico-chemical phenomena changes in the matter or form of the 

 fundamental life-stuff." 



From this curious, though keen, critical, and constructive essay, 

 I quote as follows : 



"Der Begriff der Entwickelungsschraube deckt sich eigentlich 

 vollig mit dem Begriff der Selbststeuerung der lebendigen Natur; 

 ich halte aber mit gutem Grunde beide Ausdrucke aufrecht, weil 

 sie einer verschiedenen Betrachtung entspringen, namlich die 

 Selbststeuerung der mechanischen, die Entwickelungsschraube der 

 historischen, entwickelungsgeschichtlichen Betrachtungsweise ; die 

 Selbststeuerung ist das Prinzip der Herstellung des Gleichgewichtes 



* This has been corroborated by M. Languet with the carrot. Soc. 

 Roy. et Cent. d'Agricult., 2d ser., Vol. II, 1846-7, p. 539. 



