130 STUDIES IN ANIMAL LIFE. 



Thus I have had the long tentacles of a Terebella (a 

 marine worm) living and wriggling for a whole 

 week after amputation.* In speaking of the inde- 

 pendence of an organ, I must be understood to mean 

 a very dependent independence; because, strictly 

 speaking, absolute independence is nowhere to be 

 found ; and, in the case of an organ, it is of course 

 dependent on other organs for the securing, prepar- 

 ing, and distributing of its necessary nutriment. 

 The tentacles of my Terebella could find no nutri- 

 ment, and they perished from the want of it, as the 

 Terebella itself would have perished under like cir- 

 cumstances. The frog's heart now beating on our 

 table with such regular systole and diastole, as if it 

 were pumping the blood through the living animal, 

 gradually uses up all its force ; and since this force 

 is not replaced, the beatings gradually cease. A 

 current of electricity will awaken its activity for a 

 time, but at last every stimulus will fail to elicit a 

 response. The heart will then be dead, and decom- 

 position will begin. 



Dependent, therefore, every organ must be on 

 some other organs. Let us see how it is also inde- 

 pendent ; and for this purpose we glance, as usual, 

 at the simpler forms of life to make the lesson easi- 

 er. Here is a branch of coral, which you know to 

 be in its living state a colony of polypes. Each of 

 these multitudinous polypes is an individual, and 

 each exactly resembles the others. But the whole 



* Seaside Studies, 2d edition, p. 59 sq. 



