ORTHOGENESIS 



77 



crustacean, Artemia salina, when the salt of the water it 

 lives in is increased or diminished. 1 In these various 

 experiments the external agent seems to act as a cause 

 of transformation. But what does the word &quot; cause &quot; 

 mean here? Without undertaking an exhaustive 

 analysis of the idea of causality, we will merely remark 

 that three very different meanings of this term are 

 commonly confused. A cause may act by impelling^ 

 releasing, or unwinding. The billiard-ball, that strikes 

 another, determines its movement by impelling. The 

 spark that explodes the powder acts by releasing. The 

 gradual relaxing of the spring that makes the phono 

 graph turn, unwinds the melody inscribed on the 

 cylinder : if the melody which is played be the effect, 

 and the relaxing of the spring the cause, we must 

 say that the cause acts by unwinding. What distin 

 guishes these three cases from each other is the 

 greater or less solidarity between the cause and the 

 effect. In the first, the quantity and quality of the 

 effect vary with the quantity and quality of the cause. 

 In the second, neither quality nor quantity of the 

 effect varies with quality and quantity of the cause : 

 the effect is invariable. In the third, the quantity 

 of the effect depends on the quantity of the cause, 

 but the cause does not influence the quality of the 

 effect : the longer the cylinder turns by the action of 

 the spring, the more of the melody I shall hear, but the 

 nature of the melody, or of the part heard, does not 

 depend on the action of the spring. Only in the first 

 case, really, does cause explain effect ; in the others 

 the effect is more or less given in advance, and the 



1 It seems, from later observations, that the transformation of Artemia is 

 a more complex phenomenon than was first supposed. See on this subject 

 Samter and Heymons, &quot; Die Variation bei Artemia salina &quot; (Anhang zu den 

 Ahhandlungen der k. preussischen Akad. der Wissemchaften, 1902). 



