opposed to theirs. He heaped experiment
upon experiment and argument upon argument, spicing with the sarcasm
of the advocate the logic of the man of science. In view of the
multitudes required to produce the observed results, he ridiculed the
assumption of atmospheric germs. This was one of his strongest
points. 'Si les Proto-organismes que nous voyons pulluler partout et
dans tout, avaient leurs germes dissembles dans l'atmosphere, dans la
proportion mathematiquement indispensable a cet effet, l'air en serait
totalement obscurci, car ill devraient s 'y trouver beaucoup plus
serres que les globules d'eau qui forment, nos nuages epais. Il n'y a
pas la la moindre exageration.' Recurring to the subject, he
exclaims: 'L'air dans lequel noun vivons aurait presque la densite du
fer.' There is often a virulent contagion in a confident tone, and
this hardihood of argumentative assertion was sure to influence minds
swayed not by knowledge, but by authority. Had Pouchet known that
'the blue ethereal sky' is formed of suspended particles, through
which the sun freely shines, he would hardly have ventured upon this
line of argument.

Pouchet's pursuit of this enquiry strengthened the conviction with
which he began it, and landed him in downright credulity in the end. I
do not question his ability as an observer, but the enquiry needed a
disciplined experimenter. This latter implies not mere ability to
look at things as Nature offers them to our inspection, but to force
her to show herself under conditions prescribed by the experimenter
himself. Here Pouchet lacked the necessary discipline. Yet the
vigour of his onset raised clouds of doubt, which for a time obscured
the whole field of enquiry. So difficult indeed did the subject seem,
and so incapable of definite solution, that when Pasteur made known
his intention to take it up, his friends Biot and Dumas expressed
their regret, earnestly exhorting him to set a definite and rigid
limit to the time he purposed spending in this apparently unprofitable
field. [Footnote: 'Je ne conseillerais a personne,' said Dumas to his
already famous pupil, 'de rester trop longtemps dans ce
sujet.'--Annales de Chimie et de Physique, 1862, vol. lxiv. p. 22.
Since that time the illustrious Perpetual Secretary of the Academy of
Sciences has had good reason to revise this 'counsel.']

Schooled by his education as a chemist, and by special researches on
the closely related question of ferme