August 13, 1885 | 
NATURE 339 
succinct account of the various classes of pharmaceutical 
preparations, with tables of doses of the individual 
members of each. 
The rest of the book is chiefly taken up with an account 
of the preparation, characters, doses, actions, and uses of 
the various remedial agents. Here we find all that valu- 
able empirical knowledge of the use of drugs which 
science has so far failed to analyse, but which in course 
of time will no doubt be incorporated with the first 
section. Section III. is concerned with the inorganic 
remedies, Section V. with those obtained from plants, and 
Section VI. with those derived from animals. Section 
IV., “ Organic Materia Medica,” requires special notice. 
It includes all the carbon compounds employed in 
medicine which are obtained by synthesis. 
Pharmacology owes much to the enterprise of the 
chemist. In the first place, the extraction of definite 
active principles from the various vegetable structures 
used in the Pharmacopceia has been of inestimable value. 
It was formerly impossible to be sure that the prepara- 
tions made year by year were of the same strength. The 
environment of the plant varies more or less each season, 
so that at one time it may manufacture more of its active 
principles than at another. Moreover some plants contain 
several powerful ingredients which are of more value 
apart than together. The extraction and isolation of 
these substances has therefore led to a correct dosage 
and their more,definite application to the treatment of 
disease. 
In the second place the chemist is making us by degrees 
independent of the plant world by producing synthetically 
the bodies thus isolated. Just as the manufacture of 
alizarine from anthracene made the dyer independent of 
the madder root, so the artificial production of salicylic 
acid has supplanted the willow. In course of time, no 
doubt, as Dr. Brunton suggests, this section of Materia 
Medica will develop greatly, whilst the number of animal 
and vegetable preparations will correspondingly diminish. 
We are not, however—thanks again to chemical research 
—limited merely to those principles already in the Phar- 
macopeeia. Already we are supplied with a host of sub- 
stances, the products of synthesis, amongst which many 
of the valuable drugs of the future will doubtless be found, 
Organic synthesis, apart from the valuable substances 
which it may yield us, as the bodies kairin and antipyrin, 
which have already found their use in medicine, is of 
extreme importance to the pharmacologist from another 
standpoint, for it enables him to form conjectures as to the 
molecular structure of compounds. So far but few 
definite relations have been established between chemical 
constitution and physiological action. Still, enough has 
been done to demonstrate the existence of such relations 
and to promise a fruitful harvest hereafter. It has been 
proved, for instance (Crum Brown and Fraser), that the 
introduction of the methyl group into the molecule of an 
alkaloid gives it the power of paralysing the end-organs 
of motor nerves. Similarly Drs. Brunton and Cash have 
found as a general rule that most of the compound radicals 
formed by the union of amidogen with the radicals of the 
marsh-gas series possess a paralysing action on motor 
nerves. 
It is probable that just asin the members of homologous 
series we have a gradation of physical properties and a 
similarity of chemical reactions, so bodies having similar 
chemical constitution will be found to resemble each 
other in physiological action. Induction will then lead to 
deduction, and the paths in which we are to tread in order 
to find drugs endowed with certain properties will be indi- 
cated ; in illustration of this we note that already we know 
where to experiment if we wish to add to the number of 
our anesthetics and antipyretics. 
This review could not well close without a reference to 
the many useful illustrations and to the elaborate indices 
(extending to 131 pages), which add materially to the 
value of the work. It will rank as the text-book on the 
subjects of which it treats, being at once the best exponent 
of existing knowledge and a powerful stimulus to further 
progress. ARTHUR GAMGEE 
ELEMENTARY PRACTICAL PHYSICS 
Lessons in Elementary Practical Physics. By Balfour 
Stewart, M.A., LL.D., F.R.S., Professor of Physics 
Victoria University, the Owens College, Manchester, 
and W. W. Haldane Gee, Demonstrator and Assistant 
Lecturer in Physics, the Owens College. Vol. I. 
(London: Macmillan and Co., 1885.) 
N this the first volume of what will evidently be an 
elaborate work on practical physics, the authors have 
treated of general physical processes only, ze. of the 
methods employed in the laboratory for the exact deter- 
mination or measurement of the geometrical and mechan- 
ical properties of bodies. It is impossible to over-estimate 
the importance of these fundamental measures, for upon 
them depends the accuracy of almost all physical work. 
That this is the view of the authors is made evident by 
their having devoted nearly the whole of the first volume 
out of a promised three to matters purely geometrical 
and mechanical. Throughout the volume the most minute 
attention to details is apparent, so much so that it is likely 
to weary those who read it only; but those who use it to 
guide them in making the measures given will certainly 
benefit by the completeness with which each subject is 
treated. 
The first chapter, on the measurement of length, may 
be taken as a type of the whole volume. The metre and 
the yard are first defined and their absolute relation 
stated; the actual relation of metre and yard scales— 
slightly differing from the absolute owing to the fact that 
o° C. and 62° F. are the two temperatures of reference—is 
next explained. A paragraph on “end measure” and - 
line measure” concludes what is in effect an introduc- 
tion to the first chapter. Then the “Lessons” in this 
chapter begin. The first lesson is on the use of scales. 
In this instructions are given for measuring a length with 
a pair of compasses and an ordinary or a diagonal scale. 
Results are given showing the limit of accuracy by this 
method. The second lesson is on the straight Vernier, 
the third on the barometer Vernier, the fourth on the 
spherometer, and the fifth on the micrometer wire gauge. 
Lesson 6 is a description with figures of the dividing 
engine of M. Perreaux, the use of which is the subject of 
the next lesson. The next five lessons of this chapter 
explain the copying of scales, the cathetometer with its 
adjustments, the micrometer microscope, the Whitworth 
measuring machine, the eyepiece and stage micrometer, 
