Marks , employed for classifying the Schizomycetes. 1 3 1 
owe very largely to the efforts of the non-botanists as well as 
to those of the botanists. 
Some of these characters had already been drawn into use, 
e. g. the chromogenic, zymogenic, or pathogenic powers, but 
there are others which are coming more and more into use as 
the subject progresses. Such are the shapes, colours, and 
mode of extension of the colonies in the mass, when grown 
on certain solid media, and especially gelatine and agar-agar : 
the powers of the colonies to liquefy the gelatine, by pepton- 
ising it, and the shapes and mode of progress of the 
excavations made. We owe nearly all these characters, and 
especially the systematisation of them, to the non-botanists 
of the Koch-Fliigge school. 
Then, again, more attention is being paid to the tempera- 
tures at which the cultures flourish — the optimum-temperatures 
as Sachs has it. There are forms which will grow at tem- 
peratures as low as o° C., and there are others which will grow, 
not merely live but grow, at 6o° to 70° C. and even slightly 
beyond, e. g. Miquel’s Bacillus thermophilus ; and a whole 
host of species are known which flourish below 20° C., as 
contrasted with species which require 30° or 40° C., and some- 
thing has been done towards utilising these characters for 
classifying the Schizomycetes. 
Every one now knows that, as Pasteur first discovered, 
some Bacteria are anaerobic, while others are aerobic, faculta- 
tive or obligate in each case as may be, and these peculiarities 
have been pressed into the service. 
Miquel has, only this last year, proposed to employ such 
characters as the above for drawing up a £ bacterial flora/ for 
the use of specialists who are engaged in the analysis of 
water. As it is both interesting and instructive — I shall 
criticise some of the points later on — I have appended the 
outline in Table VIII. 
K 2 
