Marks , employed for classifying the Schizomycetes . 107 
of evidence is accumulating which must have, and is having, 
its effect in checking mere recording of forms, on the one 
hand, and wild speculations on the other. 
The second double set of observers, which we may call the 
non-botanists — without implying the slightest want of respect 
for the magnificent edifice of knowledge which they have 
erected — may, it seems to me, be said to have taken their 
origin from two sources. One of these sets, which has 
culminated in the grand school now centred in the Pasteur 
Institute in Paris, sprung quite naturally from the epoch- 
making work of Pasteur on fermentations \ and its leading 
characteristics are unquestionably derived from the teachings 
and writings of the illustrious master who still directs the 
school. We may, I think fitly, denominate it the school of 
Pasteur and Duclaux. Its leading feature, and the one which 
binds it together as a very compact body, is the concentrated 
attention to the processes of zymotic energy displayed by 
micro-organisms. It has concerned itself very little with 
questions of morphology, and still less with the interests of 
the systematists, towards whom, in fact, its attitude seems 
occasionally somewhat supercilious. 
Since I am committed to the invidious task of reminding 
my readers of some of the leading work of each set of 
investigators, it is only necessary to point to the following 
as examples of the magnificent achievements of the Pasteur- 
Duclaux school : the works of Downes and Blunt, Arloing, 
Duclaux and Roux on the action of light on the spores of 
Bacillus anthracis ; Schloesing and Muntz, Warrington, 
Frankland and Winogradsky on nitrification ; Metschnikoff 
on phagocytes ; Tyndall on dust; Hansen on yeasts; and 
many others influenced by the author of the classical works, 
Etudes sur le Vin, Etudes sur la Biere, and the director 
of the great experiments on hydrophobia now being carried 
out. It is unnecessary to go into the details of Pasteur’s 
labours on anthrax, fowl-cholera, vaccination, immunity, 
1 It is therefore pre-Cohnian in many respects, though it touches Cohn’s work, 
and that of his contemporaries, at many important points. 
