424 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1941 



Gracilaria spinosa, one of the jelly-forming algae. Occasionally, the 

 layman confuses seaweed nests with the nests that are used for 

 bird's-nest soups, but actually they are very different from each 

 other. 



"Can-can" is the peculiar dry and tangled egg mass of the volador 

 or flying fish which is collected in season and dried so that it may 

 be kept in the market throughout the year. This product has long 

 been familiar to the natives of Peru. The egg mass is usually found 

 entangled in the seaweed. 



During World War I, peoples in Europe found it necessary to 

 turn to seaweeds for a source of nourishment. According to Alsberg, 

 there is no proof that seaweeds have more than a moderate food 

 value although their value as an antiscorbutic, similar to cabbage 

 and lettuce, is appreciated. Very little is known about the proteids 

 of seaweeds, but according to Cameron, they do not begin to approach 

 the food value found in 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 pectins and hemicelluloses ; it 

 dissolves readily in boiling water and forms a jelly when cold. 

 Because of this property of jellification, the attention of experts has 

 been directed to the utilization of seaweeds both in cookery and in 

 various commercial preparations. 



Very little is known about the chemical composition of these mem- 

 branes. Among the green seaweeds, the cellulose is associated with 

 hemicellulose, a substance that is soluble in 3 percent sulfuric acid 

 solution and contains a great abundance of xylane. There is also 

 an insoluble portion rich in dextrane. Another hydrocarbon that 

 has been detected in Fucus is called fucine. It is soluble in 1 percent 

 sulfuric acid, turns blue with iodine, and is localized in the middle 

 lamella. Dextrose and methylfurfurol occur in the brown algae. 

 The red seaweeds, according to Perrot and Gatin, contain galactans, 

 mannans, levulosans, dextrans, and sometimes methylpentosans. 

 Some of these complex carbohydrates are a possible source of energy, 

 but their extent is still unknown. Fat is a negligible quantity. The 

 analyses given below show what little justification there is in arguing 

 for the food value of algae. 



Table 1. — Analysis of Turrentine {Cameron) 



Gelidium corneum 



Percent 



Water 22. 29 



Protein 6. 85 



Carbohydrates 60.32 



Ash 3.81 



Fiber 6. 73 



I 



