262 



EDUARD UHLENHUTH 



a similar case (experiment 13) and we will find a few more 

 animals acting similarly. All individuals which developed 

 their spots after the graft had developed them, showed one 

 common characteristic when they were fully metamorphosed: 

 they were almost bare of yellow pigment. The host of experi- 

 ment 45 for instance, developed only very small, and faint spots 

 which lacked the usual compactness of the spots and gave only 



the impression of an accumulation of little yellow dots on the 

 black background. As their number (on the right side) was 

 only 3 (fig. 9), the animal appeared almost uniformly black. 

 We believe therefore that in this case a factor whose nature will 

 be explained later on, interfered with the metamorphosis factor. 

 In experiment 46 the graft did not develop ariy real spots, but 

 only a few small dots which appeared simultaneously with the 



