y accumulated. In doing this, however, I have been guided by a
pretty intimate knowledge of the wants of the farmer, which has induced
me to enlarge on those departments of the subject which bear more
immediately on the every-day practice of agriculture; and for this
reason the composition and properties of soils, the nature of manures,
and the principles by which their application ought to be governed, have
been somewhat minutely treated.

In all cases numerical details have been given as fully as is consistent
with the limits of the work; and it may be right to state that a
considerable number of the analyses contained in it have been made in my
own laboratory, and that even when I have preferred to quote the results
of other chemists, they have not unfrequently been confirmed by my own
experiments.

UNIVERSITY OF GLASGOW,
_1st November 1860._

CONTENTS.

Page

INTRODUCTION 1

CHAPTER I.

THE ORGANIC CONSTITUENTS OF PLANTS.

Carbon ... Carbonic Acid ... Hydrogen ... Nitrogen ... Nitric Acid ...
Ammonia ... Oxygen ... Sources whence obtained ... The Atmosphere ...
The Soil ... Source of the Inorganic Constituents of Plants ... Manner
in which the Constituents of Plants are absorbed 8

CHAPTER II.

THE PROXIMATE CONSTITUENTS OF PLANTS.

The Saccharine and Amylaceous Constituents ... Cellulose ... Incrusting
Matter ... Starch ... Lichen Starch ... Inuline ... Gum ... Dextrine ...
Sugar ... Mucilage ... Pectine and Pectic Acid ... Oily or Fatty Matters
... Margaric, Stearic, and Oleic Acids ... Wax ... Nitrogenous or
Albuminous Constituents of Plants and Animals ... Albumen ... Fibrine
... Casein ... Diastase 40

CHAPTER III.

THE CHANGES WHICH TAKE PLACE IN THE FOOD OF
PLANTS DURING THEIR GROWTH.

Changes occurring during Germination ... Changes during the After-Growth
of the Plant ... Decomposition of Carbonic Acid ... Decomposition of
Water ... Decomposition of Ammonia ... Decomposition of Nitric Acid 54

CHAPTER IV.

THE INORGANIC CONSTITUENTS OF PLANTS.

The Amount of Inorganic Matters in Different Plants ... The Relative
Proportions of Ash in the Different Parts of Plants ... Influence of the
Nature of the Soil on the Proportion of Mineral Matters in the Plant .