SOURCES, PREPARATION, AND PROPERTIES OF SOME 

 ALGAL GELATINES/ 



By Irving A. Field, 



Late Professor of Biology, Clark, College, and Special Investigator, U, 8. Bureau 



of Fisheries. 



INTRODUCTION. 



Many seaweeds when boiled in water yield a highly gelatinous 

 product called gelose, which is employed in various ways in science, 

 medicine, and commerce. The jellies of the different species of 

 algse varj'- somewdiat in chemical composition and have quite dif- 

 ferent physical properties. In general, however, gelose will absorb 

 water and swell up but not dissolve unless heated almost to boiling. 

 The solution coagulates on cooling to a more or less colorless 

 translucent jelly. The gelatinizing poAver in some cases is more 

 than 10 times that of ordinary animal gelatin. Algal gelatines 

 lose their property of gelatinizing when heated with water under 

 a pressure of six atmospheres or when boiled with dilute acids or 

 alkalis. In a hot solution of dilute hydrochloric acid they yield 

 galactose. Treated w^ith nitric acid they yield mucic and oxalic 

 acids. Some of the American seaweeds that yield gelose are dis- 

 cussed below. 



IRISH MOSS. CHONDRUS CRISPUS. 



Carrageenin is the name given to the gelatinous extract of Irish 

 moss which grows in abundance on the rocky portions of the North 

 Atlantic coast just below low-tide mark. The chief source of supply 

 is centered around Scituate, Mass., where about 30 or more men are 

 engaged in moss collecting. Other localities where the moss is har- 

 vested are Cape Porpoise, Portsmouth, York, and Rye^ N. H. ; Cape 

 Sable, Rockport, Gloucester, Marblehead, Nahant, Cohasset, Ply- 

 mouth, White Horse Beach, and Cuttyhunk Island, Mass. ; Block 

 Island and Montauk, N. Y. 



The moss is scraped from the rocks by means of a special rake and 

 spread on a clean sandy beach where it is washed in sea water and 

 sundried alternately several times until bleached white. Dew or 

 light rain assists in the bleaching process, but a heavy rain will ruin 

 the product by extracting the jelly and giving the moss a yellowish 

 discoloration. When ready for market it is packed in barrels or 

 bales weighing about 100 pounds each. In this condition it sold for 

 about 10 cents a pound in 1920. 



Chemical analyses show that fresh Irish moss contains T9 to 80 

 per cent water. The water- free substance is composed of : 



Por cent. 



Gelatinous matter 65 



Nitrogen 2-3 



Lipoids 0.7-1 



Ash 10-15 



^ Appendix VI to the Report of the U. S. Commissioner of Fisheries for 1922. B. P. 

 Doc. No. 029. Fir.st is.sucd as an Economic Circular (No. 51, supply exhausted). 



99910°— 22 1 



