Vice-President’s Address. 11 
actual contagium of certain eruptive diseases and of acute 
fevers, but also, as had been pointed out by Andry, the 
exciting causes of both fermentation and putrefaction. 
Many attempts were made to classify the organisms that 
had made such a stir in the scientific world, and Miiller of 
Copenhagen was at length able, about one hundred and four 
years ago, to reduce to scientific and systematic order what 
had hitherto been merely chaos. 
Although it was held, even at this early period, that these 
organisms were the causes of fermentation and putrefaction, 
there were many differences of opinion as to how they were 
developed, whence they came, under what conditions they 
could live, and how they carried on their work. Whether 
they were the result of spontaneous generation, or were 
the progeny of pre-existing forms, was the question which 
for over a century occupied the minds of those engaged in 
scientific research and speculation. Some observers con- 
sidered, though they had no great amount of evidence to 
adduce in support of their theory, that bacteria were the 
progeny of minute organisms which were present in myriads 
in the air, from which they were deposited on fruits, plants, 
and other matter, and whence they made their way into the 
various infusions prepared for them. In this country a 
prophet arose in the person of Dr Needham, who was really 
the first to suggest an attempted solution of the question by 
a theory of abiogenesis or spontaneous generation. Needham 
at first thought that these vibriones or “ plant-animals,” as he 
called them, arose from plants by special vegetative power, 
and that from the plant-animals, by a process of evolutionary 
accretions, other organisms again arose. He tried to prove, 
by boiling a beef infusion and then keeping it and allowing 
it to putrefy in a well-stoppered bottle (a most scientific 
method), that these zoophytes could not owe their origin to 
germs which outside insects or organisms had brought into 
the infusion, as he considered that the boiling should have 
destroyed the germs originally in the fluid; and as no new 
germs could, he thought, make their way into the closely- 
stoppered vessel, the resulting organisms must be the result 
of the action of a special vegetative force. To very critical 
