BACTERIAL CONTENTS OF VARIOUS WATERS 115 



gelatine-plates consisting of these three forms (see 

 pp. 454-456). 



Eussell has more recently 1 extended his investiga- 

 tions to an examination of the sea-water and mud 

 in the vicinity of Wood's Holl, Massachusetts. The 

 number of microbes present in these more northern 

 and cooler waters was markedly less at this point than 

 in the Mediterranean. The slime from Buzzard's Bay 

 yielded an average of 10,000 to 30,000 bacteria in 1 

 c.c., which Eussell says represent but a small fraction 

 of those present in the Mediterranean mud at equal 

 depths. Here again two species were found to be 

 specially prevalent in the water, together with two or 

 three other forms occasionally met with. The mud also 

 contained these two prevailing water forms, but another 

 form, an indigenous slime bacillus, occurred in such 

 large numbers as to make up from thirty to fifty per 

 cent, of the whole quantity present. 



Samples of mud were also obtained, about 100 miles 

 from the shore at the depth of 100 fathoms, on the 

 edge of the great continental platform skirted by the 

 Gulf Stream. These samples are the farthest from land 

 that have ever been bacteriologically examined, and 

 bacteria were present in large numbers ; moreover, the 

 two prevailing species present were identical with those 

 obtained near the shore at Wood's Holl.' 



Eussell mentions that the Cladothrix intricata (see 

 p. 517) was only rarely met with, whereas in the 

 Mediterranean mud it was frequently found. 



On comparing these results with those already 

 referred to for fresh-water lakes, it will be seen that 

 the distribution of bacteria in the two cases is sub- 

 stantially similar, both the lake and the ocean at a 



1 Botanical Gazette, vol. xvii. p. 312. 1892. 



i 2 



