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PROGRESS OF MICROSCOPICAL SCIENCE. 
is a wholly erroneous idea. The question of abiogenesis will still 
remain after all have acquiesced in Pasteur's views of the origin of 
bacteria : indeed, to a logical evolutionist there would appear to be a 
strong a priori improbability in the abiogenic origin of bacteria. 
They were not wanted, and could not exist, on the earth's surface 
until after other organisms had lived and died before them. Their 
special function and feeding-ground lie amid the wreck of living 
things. And if the survival of the fittest hold good in regard to 
bacteria, they must be the remote progeny of less perfect organisms 
of the same class. What can be more perfect than their adaptability 
to their place and use in the order of nature ? They resist, in certain 
media, for considerable periods the heat of boiling water ; they 
multiply with incredible speed ; their germs survive in countless 
myriads in the dust of the atmosphere ; they float in every drop of 
water on land and sea ; they appear to be omnipresent and almost 
indestructible. Those who are in search of a case of abiogenesis 
should seek among the primitive organisms — if there be any such — 
which can exist and grow amid inorganic elements, in the water of 
the sea, or the mineralized springs and streams of the land. When 
Pasteur says that abiogenesis is a chimera, he prudently adds, " in 
the present state of science;" and even thus qualified, the expression 
is perhaps too strong. But it is absolutely certain that up to the 
present time no case of abiogenesis has been presented which has 
stood the test of accurate investigation ; nor can it be doubted that, 
in so far as the antiseptic treatment of disease rests on the origin 
of bacteria, the advocates of that treatment stand on unassailable 
ground. 
PoUen-tuhes for the Microscope. — Mr. J. O'Brien writes to the 
' Garden ' (August 19) as follows : — " I lately came across a passage in 
a popular work on microscopy recommending the student who wishes 
to examine the pollen-tubes of flowers to dissect a fertilizing stigma. 
Remembering my own early experience in this branch of microscopic 
preparation, my repeated disappointments after wasting my time in the 
most tedious manifestation, besides having seen the preparations of 
others who followed this method of procedure always end in failure, I 
am induced, more especially at this season of the year, when the 
opportunities of studying the pollen of plants are so many, to offer a 
few hints on a new method of observing these beautiful objects. Most 
persons must have noticed that when the stigmas of Lilium and other 
flowers have arrived at the period of fertilization, a drop of nectar 
makes its appearance at their top. This nectar is the one thing 
necessary for exhibiting the growth of the pollen-tubes. We will 
take for example the Lilium speciosum or L. auratum, as they usually 
produce the most nectar. If a plant or two coming into flower be put 
into the greenhouse instead of leaving them outside where the flies 
will help themselves to the nectar, we shall find that in a few days 
several stigmas will be ready with the drops pendent. Take an ordi- 
nary microscope slide and place the centre of it against the most 
liquid drop, which will remain on the glass ; if not sufficient, another 
drop should be added from another pistil. Then touch the point of 
