318 The Botanical Gazette. [October, 
cent. of the whole number present, and is an indigenous slime 
bacillus. Besides this species there are two or three 
other species that are exclusively mud inhabitants although 
soil and carries them about in the air. ; 
The presence of these zzdigenous mud forms necessarily 
implies that they exist in a vegetative condition, but this can 
also be experimentally determined. Samples of the mud 
were taken and treated in the ordinary way in which cultures 
were prepared. The diluted material was then heated at a 
temperature sufficiently high to kill all the vegetative forms 
(80°C) but not enough to destroy the vitality of the spores. 
Cultures were then immediately made from the heated material 
and the actual condition of the individuals as they existed in 
the sample used, could thus be ascertained. hese two sets 
could then be directly compared and the difference in the number 
of colonies gave the approximate number of vegetative ber 
actually present in the water or mud. This proportion Is 
often a widely variable one but the analysis of a score o 
more samples show that the mud bacteria as well as the water 
: : . iti VEN = 
forms are in a large degree in a vegetative condition, ¢ 
under such adverse conditions for their development as those 
that are found at the bottom of the deep s€3. or 
Mention has only been made so far, of the distribution . 
marine bacteria in general, but the vertical range 
ath : ies in 
depth limits of growth, which each species possesses, varies 
different cases. ange if 
