4S THE MARINE ALG.T5 OF GUER^s^SEY 



were obtained from seaweed. Mr. Besfs success in extracting potash 

 with the methods at his disposal, justify one in raising the question 

 whether the vast quantities of weed that are allowed to rot on our 

 coasts might not be utilized to some profit. He was of the Oi^inion 

 that this might be done if the problem of labour could be solved. 



Manure. — The farmers plough the weed into the ground and use it 

 in a general way. There is an old Guernsey saying : " No seaweed 

 no corn3'^ard." The advantages of using seaweed as manure are 

 detailed in a pamphlet published by the Board of Agriculture and 

 revised w]) to 1913. It contains much valuable information as to 

 chemical constituents, etc. 



Fodder. — Although it is known that the sheep on L'Ancresse 

 common stray over the shores and browse with gusto on the Fuci, 

 nothing is done on the island by way of utilizing seaweed as fodder. 

 Fucus vesiculosus might well be used for this purpose in winter, while 

 Chondnis crispus is valuable in fattening calves and pigs. Inci- 

 dentally, it is interesting to note that successful experiments have 

 recently been made with Laminarias as forage for horses instead of 

 oats. The algse were prepared and given to the animals, who accepted, 

 digested, and assimilated the novel food. 



Food for JI/^J^.— Considerable attention has been directed towards 

 the use of seaweeds as food for man, more especially during the late 

 War. According to Alsberg there is no proof that seaweeds have 

 more than a moderate food- value, though they have a considerable 

 vakie as antiscorbutics like cabbage and lettuce. Almost notiiing is 

 known about tlie proteids of seaweeds; but according to Cameron 

 they have not anything like the food value of cereals. The value of 

 seaweeds as a food is to a large extent due to the mucilage produced 

 by the membranes of the cellular tissue, which is rich in pectics and 

 hemicelluloses ; it dissolves readily in boiling water and forms a jelly 

 when cold. On account of this property the attention of experts is 

 being directed towards the utilization of seaweeds both in cookery and 

 in various commercial preparations. 



Very little, however, is known about the chemical composition of 

 these membranes. Among the green seaweeds the cellulose is asso- 

 ciated with hemicellulose, a substance soluble in 8V^, sulphuric acid 

 iind containing a great abundance of xylane ; there is also an in- 

 soluble portion rich in dextrane. Another hydrocarbon which has 

 been detected in Fucus is called *' fucine " ; it is soluble in 17o sul- 

 phuric acid, and turns blue with iodine ; it is localized in the middle 

 lamella. Again, dextrose, and methylfurfurol occur in the brown 

 algiB. The red seaweeds, according to Perrot & Gatin, contain 

 galactans, mannans, lajvulosans, dextrans, and sometimes methyl- 

 pen tosans. Some of these complex carboh^^drates are a possible 

 source of energy, but how far is not known. Fat is a negligible 

 quantit}^ 



As regards the general constituents of seaweeds, the analyses 

 below indicate to some extent how far one is justified in considering 

 the value of seaweeds as food. 



