PROGRESS IN BIOLOGICAL INQUIRIES. 29 



sphere of jictivity of another office of the Bureau, the further history 

 of the matter does not pertain to this report. 



JELLY FROM SEAWEEDS. 



During last summer Prof. Irving A. Field conducted for the 

 Bureau, in connection with the AVoods Hole laboratory, investiga- 

 tions concerninof the feasibility of derivin<T from marine algae a 

 gelatin suitable for use in the preservation of fish. The experiments 

 of commercial packers have previously indicated that animal gelatins 

 liquefied at such low temperatures that they could not be employed 

 for this purpose. The jelly is not ordinarily used as a preservative 

 in a strict sense, but as a medium in which the preserved fish are 

 held and prevented from breaking to pieces in shipment. 



Of all the algae of the New England coast employed in the investi- 

 gation only the Irish moss (Chondrus crispus) yielded gelatin — or, 

 more correx^tly, gelose — in commercial quantities. It was found that 

 Irish moss contained 79 per cent water and that the desiccated mate- 

 rial was approximately 65 per cent gelose. The gelatinous extract 

 from Irish moss is commonly known as " caragenin," but Dr. Field's 

 experiments indicate that it is closely comparable to agar-agar. 

 Agar-agar is made in Japan from another seaweed, Gelidium cor- 

 nsuTTh^ which is found to some extent on our Pacific coast and, in 

 limited quantities, on the Atlantic coast. 



The investigation developed provisional methods of preparation 

 of caragenin, and a series of tests showed that \\ grams of the dried 

 extract added to a 14-ounce can of fish was sufficient to form a firm 

 jelly that prevented such soft fish as whiting and herring from break- 

 ing to pieces when subjected to the rough treatment of being trans- 

 ported 400 miles in the back of an automobile. The jelly in no way 

 impaired the condition or the flavor of the fish. The preparation 

 of the jelly in a form satisfactory for commercial uses remains to be 

 investigated to a further stage. Other problems arising from the 

 investigation relate to the decolorizing and purification of the jelly 

 to adapt it for other possible uses. Experiments will also be made 

 with other seaweeds from both coasts of the United States. 



UTILIZATION OF FRESH-WATER TURTLES. 



A relatively unutilized food resource is found in the several species 

 of turtles of our fresh-water streams and lakes, notwithstanding that 

 their near relative, the diamond-back terrapin of the sea coast (not 

 to mention the highly prized green turtle of the ocean) is the greatest 

 delicacy of the fish markets. In the endeavor to direct proper atten- 

 tion to this source of meat supply and to furnish the information 

 requested by many correspondents, assistants were designated to in- 

 vestigate market and fishery conditions, particularly in the Missis- 

 sippi Basin. The report by H. Walton Clark, scientific assistant, 

 and J. B. Southall, shell expert, comprises information regarding the 

 distribution and habits of the most useful species, an account of the 

 seasons and methods of capture and marketing, and data concerning 

 the preparation of the meats for use as food." The report will 



o Clark, II. Walton, and .John B. Southall. Fresh- Water Turtles : A Source of Meat 

 Supply. Appendix VII, Report, U. S. Commissioner of Fisheries, 1919, 20 pp. Wash- 

 ington, 1920. 



