THE PURIFICATION OF THE BLOOD, ETC. 53 



formidable even to fishes, which are grasped 

 and engulped. It is thus that the rhizostoma 

 travels and supports its existence. The Rhizos- 

 toma Cuvieriy common in our seas, attains to a 

 large size and weighs several pounds, and is 

 often thrown upon the beach ; but when the 

 water contained in its filmy cellular tissue is 

 exhausted by evaporation in the heat of the 

 sun, or becomes drained away, the mass of four 

 or five pounds is reduced, as we have pre- 

 viously observed, to a sort of cobweb. Here 

 the fluid contained in the filmy cellular tissue 

 is in some mysterious way connected with 

 vitality and the performance of organic func- 

 tions ; and though no nerves or muscles are 

 apparent in this strange structure, yet volun- 

 tary locomotion, contractility, and the power of 

 preying upon fishes, are possessed. It does not, 

 however, appear that the rhizostoma is endowed 

 with feeling in the genuine sense of the word. 



In the sea-anemones (Actinia) it has been 

 asserted that a low nervous system has been 

 detected ; certainly muscular fibres arc present ; 

 yet granting the existence of the former, light 

 could not be felt by means of it ; nevertheless, 

 it is light that invites these beautiful animals to 

 expand like flowers, and adorn with their love- 

 liness the rocks to which they are attached. 

 A passing cloud, obscuring the rays of the sun, 

 causes them to contract their many tinted tenta- 

 cles, and shroud themselves in their outer 

 tegument. We are here involuntarily reminded 

 of plants. How many flowers, folded up during 



