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REVIEWS. 
medicinal salts and alkaloids, has compiled a series of tables, 
wherein the characteristic reactions of such bodies are given 
in the simplest and briefest language. 
We believe that these tables will not merely render good 
service to the student, but likewise to the practitioner, by 
whom they will be doubtless consulted. 
How Crops Grow : a Treatise on the Chemical Composition , 
Structure , and Life of the Plant, for Agricultural Students. 
By Samuel W. Johnson, M.A., Professor of Agricultural 
Chemistry in the Sheffield Scientific School of Yale Col- 
lege. Adapted for English use by A. H. Church, M.A., 
Professor of Chemistry at the Royal Agricultural Col- 
lege, Cirencester, and W. T. T. Dyer, B.A., Professor of 
Natural History at the Royal Agricultural College, Ciren- 
cester. London : Macmillan and Co. 1869. 
When we consider how greatly the health and prosperity 
of a nation depend upon the successful cultivation of the art 
of agriculture, it seems marvellous that, until within compa- 
ratively few years, little or no attention should have been 
paid to the principles by which it is governed. This condi- 
tion of things was, at one time, doubtless due to agriculturists 
being ignorant of the proper means of research ; and the reason 
why rational agriculture has not made even greater advances 
in modern times than it has is, we believe, the same as that 
which has greatly contributed to retard the progress of vete- 
rinary medicine and the social elevation of its followers. 
We refer to the persistent discouragement, except by a few, 
of a knowledge of the various branches of natural and experi- 
mental science. 
The work now before us will enable any unprejudiced 
reader to see the great extent to which botanical, physiologi- 
cal, and chemical science has contributed to acquaint us with 
the laws of plant-life, as well as to comprehend the ra- 
tionale and improvement of many of the methods used in 
practical agriculture. For those who have not enjoyed the 
advantage of scientific training, the author has sought to 
unfold his subjects by such regular and simple steps that any 
one may easily master them.” By way of comment upon 
this statement, we can only say that we consider that Pro- 
fessor Johnson has been eminently successful in the accom- 
plishment of his task. The clearness of style and arrange- 
ment, as well as the numerous and w r ell- executed woodcuts 
