AGGREGATIONS OF HIGHER ANIMALS 97 



the conditioning fishes remove some harmful sub- 

 stance, but of this we have no real evidence. 



Whatever the explanation, we are certain of the 

 facts, and we know that we have demonstrated a de- 



EFFECT OF PROTEIN EXTRACT FROM SKIN OF 

 GOLDFISHES ON GROWTH OF GOLDFISH 



NO. 56 59 



EXTRACT 



VS. ■■ P= 0.0106 



CONTROL 



. 



GROWTH 1,95 0.54 



NO. 61 122 



EXTRACT 



VS. 



SALT CONTROL 



GROWTH 3.22 0.61 



P= 0.0006 



NO. 26 28 



EXTRACT 



VS. 



CONDITIONED 



WATER 



II 



GROWTH 1.92 1.55 



P= 0.26 



Fig. 15. An extract from the skin of goldfish fre- 

 quently has growth-promoting power. The arrangement 

 of the figure is on the same plan as was used in Fig. 14. 



