FUNCTIONS OF SEA-WEED. 493 



weeds. The quantity of potash is also great, 

 much greater than is contained in sea- water : 

 the fucoidal plants contain two and a half per 

 cent, of this element. They also contain a con- 

 siderable portion of magnesia, which occurs in 

 great quantities of sea-water, and not as is the 

 case with regard to lime being removed by 

 animal life, it would accumulate to a vast extent 

 in the sea but for these plants which absorb it. 

 They also contain a portion of phosphate of lime : 

 this ingredient they separate from sea-water ; 

 it is then received by various minute creatures 

 which feed on the sea-weed, and as these form 

 the food of greater marine beings, this ingre- 

 dient becomes ultimately handed over to them. 

 Thus, just as plants act with regard to ammonia 

 in the air, the sea-weeds may be considered to 

 act with regard to phosphate of lime, a highly 

 important ingredient to animal life. They 

 absorb it from the surrounding medium ; it is 

 then received by minute creatures, crustaceous 

 animals and others living in the heaps of rotting 

 sea- weeds on our shores; to be afterwards ap- 

 propriated by the higher forms of marine life. 

 The process of conservation thus perpetually 

 going forward, not only purifies the water of the 

 ocean, and assists in maintaining it in a state 

 adapted for the existence of living things ; it 

 serves also to form a continually increasing 



