Marks , employed for classifying the Schizomycetes. 1 2 3 
Zopf’s classification, admirable as it is in many respects, is 
difficult to work in practice, because it is necessary to have 
all the stages of development before we can decide on the 
position of a species : at the same time it should be noted, 
that in this very respect it is as far ahead of the merely 
tabular classifications, used for hurriedly determining the 
name of a form, as a good Flora is ahead of a mere museum 
catalogue of plants. 
It is, in fact, just in respect of this particular attention to 
all the facts in the development of the species that Zopfs 
classification is scientifically so far in advance of his pre- 
decessors. Unquestionably it renders the problems more 
difficult, because it insists on the working out of all the 
phenomena before a species is accepted ; but, since such a 
scheme must embrace all the merely diagnostic form-char- 
acters used by the Cohn-school, it must be admitted to be 
superior to their system. The matter of difficulty of applica- 
tion, in such a connection, cannot be urged as a reason for 
desisting from obtaining and recording all that can be 
discovered regarding an organism. 
The only really valid objection to a purely scientific classi- 
fication is the old objection of the purely utilitarian ‘ practical 
man,’ and even then the validity of the objection is relative. 
This leads me to bring out the point that the bacteriologists, 
in the widest sense of the word, are really looking at the 
question of classification from at least two very different 
points of view. On the one hand we have the botanists, who 
direct their attention to the organism, the Schizomycete, 
itself, as a biological phenomenon to be examined and 
reported upon as thoroughly as possible : for them, no 
classification is complete which does not record, or (what 
amounts to the same thing) imply in its records, all the 
life-phenomena of the organism, including its pedigree. 
On the other hand we have the pathologists, hygienists, 
brewers, chemists, &c., who regard the organism simply as an 
object to be named for convenience in reference, because it 
brings about certain changes in the tissues, waters, and other 
