EXPERIMENTS UPON THE STAR-FISH. 91 



made by the bristle, and then drew its head after it, and sliding 

 sidewise along the spit, completely freed itself from its compan- 

 ion. This it did as often as the experiment was tried in that 

 way. It then occurred to Trembley that dissimilar surfaces, 

 that is, the outside of the one and the inside of the other, were 

 not so likely to grow together as similar ones ; and to put this to 

 the test, he turned one of the Hydras inside out, so that when it 

 was pushed into the cavity of the other, the surfaces of the 

 stomachs of both were brought into contact. With this condi- 

 tion the animals did not seem to be dissatisfied, since they 

 remained as they were fixed, and finally united themselves in 

 one body, and enjoyed their food in common. 



Not only, therefore, do we see that these lowly organized 

 creatures may reproduce a lost part, but that they are able even 

 to resign their individuality, in order to fit themselves for the 

 conditions in which they are placed. It would seem from this, 

 moreover, that the rank of individuality in these beings is of a 

 very low order, that they should so easily part with it, or merge 

 it into one of a complex and indefinite nature ; and it would con- 

 sequently appear to confirm what I have already said in regard 

 to the insensible gradations from the lowest to the highest de- 

 grees of individuality. 



But to proceed with the enumeration of other cases of artifi- 

 cial division, I will mention one which you can very easily ver- 

 ify in the common starfish (chap. x. fig. 109) of our coast. It 

 often happens that a specimen is found having one of the arms 

 much smaller than the others, and now and then with two or 

 three in this condition ; and rarely with only one arm out of the 

 five left, the others being represented by little points growing out 

 of the old stumps. Some kinds of starfishes suffer so little vio- 

 lence from the breaking of their arms, that, let them be ever 

 so gently handled by their captor, every limb will drop off volun- 

 tarily before the specimen can be transferred to an aquarium. 

 Of our common starfish I have, on different occasions, kept 

 specimens alive after breaking off all but one of the arms, and 

 seen the wounds heal over. I was not so fortunate, however, as 



