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334 GERM THEORY OF FERMENTATIVE CHANGES 
will be found combining all the peculiarities of that which we’ have studied. 
What fungus it is derived from, if, indeed, it have come from any (for it would’ 
be rash to assume that such an origin is universal), I have no means at present 
of knowing ; but, however that may be, it cannot but be right, where we have. , 
definite characters of bacteria, to speak of them as species as a matter of con- 
venience, just as is done of various hyphomycetous jute known to be only 
inferior varieties of ascomycetous forms. : 
What are the functions of bacteria with reference to ‘itis physiology af fungi, 
and whether a bacterium derived from a fungus is ever capable of returning 
to the form of its parent, are questions on which my investigation has thrown 
no light. 
The sketches which furnished the illustrations were all drawn on the scale 
given at the foot of Plate XIII, either by camera lucida or, in a few cases where 
the objects were in motion, by eye-piece micrometer, the magnifying power 
being 1,140 diameters. The object-glass which I employed was a tenth immer- 
sion lens manufactured by Messes. R. and J. Beck, the beautiful definition of 
which was distinctly enhanced by the use of the higher eye-piece. 
