CH. Xl] BACTERIA IX THE SEA 257 



have founded hosts of species on these characters. Very many of 

 these so-called species have probably little real value. 



The distribution of bacteria in the sea. There are many 

 isolated observations of the occurrence of bacteria in the sea, but 

 the first really extensive investigation of their presence was 

 made during the Plankton Expedition ^ Generally speaking the 

 water near the shore is richer in bacteria than that further out 

 at sea, and much richer than the water of truly oceanic areas. 

 This abundance of germs near the land is due to the drainage from 

 the land ; and also to the rich algal flora of the shore which pro- 

 vides abundant food for the micro-organisms. Estuaries on densely 

 populated parts of the coasts are rich in those bacteria which 

 abound in the excreta of man and the domestic animals. I have 

 estimated as many as 70 bacteria belonging to the Bacillus coli 

 group in 1 c.c. of the water of such an estuary. But this influence 

 of the land does not extend to more than about ten miles out to 

 sea. Thus I have made several analyses of the contents of the 

 bodies of shellfish living at this distance fi^om the shore and have 

 failed to find any evidence of the presence of intestinal bacteria,, 

 although the shellfish near the shore on such a coast are universally 

 infected with such bacteria. Generally speaking it is the case that 

 the bacteria which inhabit the intestines of land animals do not 

 find a suitable habitat in sea water and when introduced into the 

 latter they gradually die out. The experiments made at the 

 instigation of the Royal Commission on Sewage Disposal shew 

 that the pathogenic and non-pathogenic bacteria of man and the 

 higher animals do not multiply in the sea — a very fortunate thing 

 in these days of crowded watering places, and popular shellfish 

 consumption. 



Such bacteria do not occur at all in the open sea. The forms 

 which we find there are quite different. Sarcinae and Streptococci 

 were not found at all by Fischer in the open Atlantic, and other 

 cocciform bacteria occurred very sparingly. Moulds like Peni- 

 cilliuin and Aspei'gillus were observed, but it is possible that the 

 occurrence of these was due to the accidental contamination of the 

 water samples and cultures. Saccharomyces, or yeasts, were found 



^ B. Fischer, Ergehnisse Plankton Expedition, Bd. iv. 1894. 

 J. F. 17 



