50 
Pasteur and his Work, 
made in the medicine of man and animals, than that which 
has taken place during this half of the nineteenth century ; and 
to none among those who have contributed to this result is 
more credit due than to Louis Pasteur, by whom the greatest 
discoveries in the world of microscopic organisms have been 
made, the solution of intensely intricate and important problems 
effected, and the verities of nature — in her darkest and most 
baffling recesses — demonstrated in a manner which only genius 
of the highest order could suggest and execute. 
It is only too often felt by those who strive to win Nature's 
secrets, that all the great problems in natural science — such as 
the nature of heat, of light, of electricity, of gravity — and still 
more, all questions connected with life, bring us in the end, and 
frequently after but a few steps, face to face with infinity and 
mystery. It has been Pasteur's happy lot to select, or rather to 
be compelled by destiny to follow, a course which has led to 
such grand achievements, and at every stage of which he has 
left his indelible and character-mark. His progress has been 
along the path which has been already trodden by men of 
great genius, and pursued unfalteringly through weary days and 
nights, but along which the love of truth burns as a pure and a 
guiding light — that lumen siccum which Bacon insisted should 
be found in all philosophers, and which, it would seem, neither 
failure nor disappointment can quench or dim. As a repre- 
sentative of modern science, Pasteur occupies an advanced posi- 
tion. Cicero has somewhere said, " Opinionem commenta delet 
dies, naturse judicia confirmat ; " and Pasteur in his work 
appears ever to have borne in mind that speculative opinions 
have but an ephemeral duration, whilst inferences drawn from 
nature and truth remain permanently on record. 
Originally a chemist, by the force of circumstances and a 
most fortunate concurrence of events, this most distinguished 
man became a biologist, and finally a pathologist — startling 
chemists, physicists, crystallographers, and physicians, no less 
than agriculturists, with his discoveries, and conferring upon 
civilisation immediate and inestimable benefits in many 
directions, while opening up a wide region for the fruitful 
cultivation of other investigators. 
However far-extending and diverse the effects of these dis- 
coveries may be, and are, the object of this paper is limited chiefly 
to a survey of their relations to and influence upon Agriculture,, 
and to a notice of the circumstances and conditions under which, 
they were made, and the benefits likely to accrue from them. 
I have stated that Pasteur was originally a chemist ; but it 
may be mentioned that his training in this science was con- 
ducted by Dumas at the Sorbonne, and by Balard at the Nicole 
