256 EDUARD UHLENHUTH 



notes about the formation of the network of experiment 36 are 

 incomplete. 



In experiment 37 where the spots of host and graft formed 

 simultaneously, the notes about the network are missing, while 

 in experiment 38 where the network was formed simultaneously 

 in host and graft, the latter never developed any spots, thus 

 making comparison impossible. 



These 12 experiments do not permit of any conclusions as to 

 whether the metamorphosis of the skin actually is determined 

 by the body of the host, neither do they prove anything to the 

 contrary. 



3. Twenty of the remaining experiments forming ten pairs 

 were so complete as to correspond in- every respect to the plan 

 designed before the experiments were started and as will be found, 

 these experiments actually support the idea that was outlined 

 in the first pages of this article. The eleventh pair should rather 

 have been placed in the second group but for some reasons, which 

 will be understood later on it was deemed to be convenient to 

 describe the experiments 11-12 under this group. 



For each pair a brief abstract from the records collected in 

 the progress of the work is given here. 



In experiments 21-22, the hosts developed in the beginning 

 at the same rate, and so did the grafts. Later on experiment 

 22 got somewhat ahead and developed the spots three days 

 before experiment 21 and consequently the graft of experiment 

 22 also developed its spots three days before the graft of 21 did, 

 though both grafts were taken from the same animal. We must 

 admit, however, that not too much weight can be laid upon this 

 result; in the first place the animals were examined only twice 

 a week and the appearance of the spots on the graft of experi- 

 ment 21 might have been reported three days later than they 

 actually formed; in this case the spots would have formed simul- 

 taneously with the spots of the other graft. Secondly it takes 

 several days as a rule for the spots everywhere on the head and 

 body to become isolated, so that some may appear isolated a few 

 days earlier than others even in the same animal; in this case 

 the difference between the grafts might have been caused not by 



