HE PORT ON THE INDUSTRY OF MANURES. 
85 
investigation than had before been possible of the tissues and products of plants, and of 
the various transformations which those products undergo during the several stages of 
vegetal development. 
The sound physico-chemical principles thus established had the happiest influence on 
physiological investigations. The organs of plants and of animals were studied in a 
clearer light than before; and their respiratory, assimilative, and excretory processes, to¬ 
gether with the relations established by those processes between the three great king¬ 
doms of nature, were gradually made out. 
Among the many illustrious men who assisted in working out these great results, 
Lavoisier probably deserves the highest place ; not, perhaps, as the largest contributor 
of new truths to the accumulating store—though his contributions of this kind were 
many and brilliant—but because his vivid imagination, and the eminent generalizing 
powers with which he was endowed, enabled him to co-ordinate all the scattered re¬ 
searches of his time, and to display innumerable isolated facts in their true subserviency 
to general laws; so as (among other things) largely to extend our knowledge of the 
cosmic equilibrium on which sound husbandry can alone be based. Everything, indeed, 
that Lavoisier did, bore the impress of his master-mind. He it was who first applied the 
Balance to the study of the phenomena of Life. He it was who first showed that, while 
plants evolve oxygen, animals, on the contrary, consume it; carbon being oxidized or 
burned in their bodies as oil is burned in a lamp. His lofty tone of thought, and eloquent 
language, powerfully impressed his contemporaries; and chiefly to his influence and 
example the admirable researches of his age owe their high scope and scrupulous pre¬ 
cision. Science never endured a severer loss than when Lavoisier met his untimely fate. 
But his great spirit lived after him; and researches bearing upon the noble themes he 
had loved to treat were carried on, if possible, with increased activity after his death. 
The scientific records of Europe were soon crowded with fresh masses of undigested dis¬ 
covery ; and in a few years such another mind as his was wanted, to grapple with the 
growing mass of detail, and once more to create order out of the scientific chaos. 
Early in the present century England, in her turn, produced a master-mind—that of 
the illustrious Sir Humphry Davy—vast in scope and luminous in conception, as any, 
the greatest, of foregone times. Davy was well fitted to wear the fallen mantle of La¬ 
voisier, and to continue his great work. It is, accordingly, to Davy’s genius we owe that 
memorable treatise—truly described by Liebig as “ immortal ”—the ‘Elements of Agri¬ 
cultural Chemistry.’ 
In that imperishable work all the scattered results of foregone research in this branch 
of science were collected and reduced to a system,-which was extended and enriched by 
the author's own capital researches ; whereof, perhaps, the most signal (in this depart¬ 
ment of science) were his analytical investigations of soils (types of all that has since 
been done in that way) ; his capital determinations of the composition and transformations 
of vegetal products ; and his admirable experiments on the nutrition of plants, as well by 
leaf as by root. 
To the powerful impulse and just direction impressed by Lavoisier in France, and by 
Davy in England, on subsequent investigations of like kind, may be ascribed in a great 
measure their vigorous and successful prosecution by philosophers contemporary with 
ourselves. 
Of these, an encyclopaedic list cannot, of course, be given here ; and, among so many 
equally illustrious names, it would be difficult to single out a few, as types to represent 
the rest. Suffice it to say that to the exertions of these able men we owe a large pro¬ 
portion of the experimental data, on which, as on a firm foundation, the edifice of mo¬ 
dern agricultural science, physical, chemical, and physiological, has, so to speak, been 
stone by stone built up. Honour and gratitude to those who have patientl}’ hewn out 
those stones from the quarry of undiscovered truth ! 
But as the true value of the quarried stones is only made apparent by their judicious 
collocation in the edifice, according to the plan of the architect; so also do experimental 
data, separately accumulated by the toil of many, only appear in their true value and 
significance when comprehensively embraced, co-ordinated, and, as it were, fused into a 
harmonious whole, by the fiery genius of one master-mind. Such a mind was Lavoisier’s in 
the last century; such a service was rendered by Davy to our fathers ; and such, to our¬ 
selves, are the mind and the service of Justus Liebig. 
Thus have France, England, and Germany, in the course of about a century, succes¬ 
sively produced the three great Lawgivers of Modern Husbandry. 
