230 
The Present State of Agriculture 
obtainnl in a large trial-gartlon conducted by competent persons, 
to guide him, his chances of loss would be greatly diminished. 
Tlie adoption of such precautions would besides be a great boon 
to the honourable dealer, while it would help forward in no in- 
considerable degree that branch of chemical physiology which 
embraces the effects })roduced by mixtures of known and varied 
composition on different crops, in different circumstances and on 
different soils. 
Third. But I pass from this, in order that I may devote the 
small remainder of our time to the third observation I wish to bring 
before you. And I venture to propose it to an audience of 
practical farmers and of the patrons of farming, only because I 
know how much higher a tone of mind has of late years begun 
to be awakened among them, and how much fuller a sense of the 
importance of scientific knowledge even to them, and how much 
clearer a conviction of its money value to the art they live by. 
To make the field experiments of greater value, analytical re- 
searches in connection with them will often be required. These 
will best be carried on in the neighbourhood of the trial-garden, 
or in a laboratory connected with it. As may be gathered from 
what has already been stated, no theory can be propounded which 
will not require or suggest experiment in the field, and no secure 
forward step can be made in our knowledge which is not based 
upon actual trial. Independent analytical researches also require 
to be prosecuted, to aid or test which field experiments may not 
be immediately necessary, but which would be conducted under 
the most favourable circumstances, were the opportunity at hand 
of instituting such trials when thev are considered desirable. 
I might here indicate many important lines of research in which 
the conjunction of the field and the laboratory would be likely to 
lead to results of importance to practice. Hins : — 
a. The states in which their mineral and organic constituents 
exist in living plants is an inquiry of much importance, which 
has scarcely yet been asked of a single cultivated plant, and to 
Avhich it will require many yeai's of minute and careful labour to 
obtain clear and definite replies. In what state of chemical com- 
bination and of mechanical aggregation do they exist in different 
parts of the plant? How much in a soluble state in the sap? 
Of what kind ? What purpose does it serve ? Is it merely dis- 
posing other matter to form fixed parts of the plant, or is it itself 
on the way to build up such parts ? How much of the mineral 
matter present in the solid, insoluble parts, is necessary to their 
existence ? — how much is foreign unorganized matter ? — how 
much actually indicative of disease ? 
The study of the ash of plants tells us nothing of the nature or 
functions of what is burned away — whether it be of an acid or an 
alkaline nature. And yet these are all of much importance. The 
