292 THE BIOLOGY OF THE SEA-SHORE 



Sauvageau (1920) mention the formation of a company 

 " La Parisette " for the manufacture of a packing material 

 from Z. marina. In spite, however, of the excellent quality 

 of the product, the venture failed owing, thinks Gloess, to 

 difficulties of transport due to the factory not being situated 

 on the spot. 



Zostera frequently forms a portion of the plant jetsam 

 utilised by the agriculturists of the coast as manure. Though 

 containing the same fertilising elements as algae the propor- 

 tions of these are somewhat smaller, and this, added to the 

 fact that decomposition is very slow, renders the Zostera 

 less valuable for this purpose. 



Red Seaweeds. — The economic value of red algae lies 

 chiefly in the gelatinous matter or gelose contained in the 

 cell wall. The most important species is Chondrus crispus, 

 the use of which is ancient and practically world-wide ; 

 Chondrus crispus, or Carrageen moss, is one of the commonest 

 algae of our shores and occurs in the zone extending from 

 the low tide of neaps to that of springs. After being picked 

 the weed is spread on the shore, bleached and dried in the 

 sun, a certain amount of moisture being essential to the 

 bleaching process (Sauvageau, op. cit.). When boiled in 

 water the weed partially dissolves and, on cooling, forms 

 a jelly which serves a number of uses. Along with other 

 red seaweeds it is employed in the preparation of various 

 dishes, especially jellies ; as a thickening for textiles ; as a 

 vegetable glue ; and during the war it fulfilled a useful purpose 

 as a substitute for gelatine of animal origin. According to 

 Sauvageau, Chondrus crispus as it occurs in commerce is 

 almost invariably mixed with Gigartina mamillosa, which 

 it sometimes resembles very closely, the two species being 

 collected indiscriminately. 



Prof. R. W. Phillips, of Bangor University, informs us 

 that C. crispus was formerly used on the Anglesey coast as 

 a food for calves. According to Cotton, the same species 

 is prescribed in certain parts of Ireland for the treatment of 

 chest complaints. 



A species of alga familiar to most inhabitants of the 



