26 THE ROLE OF ALGAE AND PLANKTON IN MEDICINE 



than 5 per cent concentration in copepods, but is more abundant in higher 

 crustaceans. It forms the exoskeleton of copepods. Although chitin is not 

 digestible, it passes through the gastro-intestinal tract harmlessly as bulk. 



That oceanic plankton can truly be an aid to the survival of drifting 

 castaways has been spectacularly highlighted recently by the Kon-Tiki, 111 

 the Heretique, 112 and the Seven Little Sisters 113 adventures. 



Thor Heyerdahl and five companions left Callao, Peru, on April 29, 

 1947, on the raft Kon-Tiki, seeking to prove that pre _ Incan Indians could 

 well have settled the Polynesian Islands after passively drifting westward 

 on prevailing ocean currents. They landed 102 days later, physically none 

 the worse, on the Raroia Atoll in the Tuamotu Archipelago. Throughout 

 the 4300 mile journey, they collected plankton in a conical silk mesh net, 

 often getting several pounds of "porridge" in a few hours. The catch was 

 greatest at night and when the sea was cold. Heyerdahl vividly described 

 the myriads of planktonic organisms netted, stressing especially their 

 colorations and nocturnal fluorescence. Four of the six men really liked 

 plankton. The taste varied with the composition of the day's catch; it 

 ranged from that of shrimp paste to that of lobster, crab, caviar, and 

 oysters. 



Dr. Alain Bombard, a French physician and sailing enthusiast, be- 

 came obsessed with the conviction that victims of shipwreck would have a 

 better chance for survival if they became better acquainted with the re- 

 sources the sea itself offered. To dramatize his thesis, he sailed his 15-foot 

 rubber raft, the Heretique, alone from Tangier across the South Atlantic 

 to the Barbados in 1952. Although the 65-day voyage was physically 

 somewhat traumatic, Bombard sustained himself on plankton, fish, water 

 derived from fish, occasional rain water, and small amounts of sea water. 



Even more recently, William Willis, a sailor from the Bronx, fol- 

 lowed the Kon-Tiki route as the solitary passenger on the balsa raft the 

 Seven Little Sisters. He left Callao, Peru, on June 22, 1954, and arrived 



