74 MARINE PRODUCTS OF COMMERCE 



Gracilaria foliifera and Hijpnea musciformis also occur in great loose masses, 

 both in Florida and North Carolina. All these plants, however, were originally 

 attached to a stone or shell where a spore lodged. When loose and drifting they 

 continue to grow and produce spores just as do the plants that remain attached 

 through maturity. Abundant production of spores by a plant appears to be ac- 

 companied by a physiological aging and ultimate degeneration, even under ideal 

 growing conditions. Spores germinate soon after they are released if water 

 temperatures are favorable. In the fall they apparently do not germinate, but 

 spend the winter in dormancy and germinate the following spring. A few vegeta- 

 tive plants of Htjpnea may be found throughout the winter in North Carolina, but 

 very little growth occurs and little or no spore production. Gracilaria foliifera 

 occurs in good vegetative condition during the winter in North Carolina and 

 apparently grows slowly. Both G. foliifera and Hypnea reach a peak of abundance 

 in June or July, with G. foliifera sometimes persisting in large masses through 

 August or September. The heavy development of these species in the early sum- 

 mer is believed to be a result of the accumulation of spores shed late the previous 

 fall. All these plants tend to grow to maturity at about the same time. The spores 

 they shed, however, are distributed considerably in time; hence, plants that follow 

 are also distributed and another peak of abundance does not occur the same 

 season. 



California Manufacturing Process. Dry, unbleached Gelidium is soaked and 

 washed in fresh water for about 12 hours. It is then transferred to steam pressure 

 cookers to which the dilute agar solution from the third cooking of a previous 

 batch is added. The ratio of water is about 1 gallon per dry pound of Gelidium. 

 Cooking is done at 15 pounds pressure for about 6 hours. The seaweed residue is 

 saved and cooked twice more, usually 8 and 12 hours, respectively. The agar 

 solution and residue are separated by a filter screen. The crude agar solution is 

 pumped into a storage tank where it is kept hot while diatomaceous earth filter 

 aid is added and the solution agitated. As it is forced through a filter press, it 

 becomes a clear, amber liquid. It is next cooled and gelled for about 24 hours in 

 open tubs. The firm agar gel is fed to a chopper from which small pieces drop 

 into 100-pound capacity ice cans that are placed in a cold room at 14° F 

 (— 10° C) for 2 days. The frozen agar gel is thawed in tanks at about 50° F 

 (10° C) and then goes to a "dewaterer" in which it passes over a screen beneath 

 which a vacuum is applied. Excess water is drawn off the agar flakes, which are 

 retained on the screen and are conveyed to a vertical stack drier through which 

 air at 215° F (101.7° C) is forced. As the wet agar flakes, which at first con- 

 tain about 90 per cent moisture, become drier and lighter they eventually are 

 blown to the top of the stack and into the downpipe. At this point they contain 

 about 35 per cent moisture. Bleaching is then done by treatment with a 1.0 per 

 cent solution of sodium hypochlorite at room temperature, after which excess 

 hypochlorite is reduced by treatment with a sodium sulfite solution. The agar 

 flakes are again sent through the stack driers and the moisture is reduced to 20 

 per cent. The flakes are granulated in a hammer mill and are ready for market. 



North Carolina Manufacturing Process. Dry, unbleached Gracilaria confervoi- 

 des, or G. foliifera (the two are usually kept separate), is placed in wooden tanks 

 with perforated steam pipes in the bottom. The seaweed is covered with water 



