656 
x 
NATURE 
[FEBRUARY I2, 1914 
would scarcely be in a position to express the 
reactions in the form of equations. The explana- 
tions given in the text are fragmentary, and some- 
times obscure and even misleading. This lack of 
information is specially noticeable as regards the 
action of solvents. No explanations are given of 
the solvent action of ammonium chloride on the 
hydroxides of magnesium and manganese, or of 
the changes which occur on dissolving silver 
chloride in ammonia, potassium cyanide, or sodium 
thiosulphate. It is extremely doubtful whether 
the reducing action of-alkaline stannous chloride 
on bismuth hydroxide leads to the sub-oxide Bi,O,, 
or whether the interaction of potassium cyanide 
and copper salts gives rise to the double cyanide 
K,[(CN),Cu]. “Some explanation seems desirable 
for the instruction (pp. 24 and 39) to use “stale 
NH,.HCOs.” On the whole, however, the work- 
ing instructions are quite practicable, but, in the 
section devoted to the rarer elements, a distinction 
might, with advantage, have been made between 
tests requiring considerable concentrations and 
those appreciable even in very dilute solutions. 
Cerium dioxide (p. 27) is. not red unless con- 
taminated with other rare earths. The final 
sections of the book are devoted to organic quali- 
tative analysis, including tests for a typical series 
of organic acids and the characteristic reactions of 
the principal organic bases with separation tables 
for the commoner alkaloids. 
(3) In order to meet the requirement of students 
of medicine whose time for the study of chemistry 
may not exceed six months, the author has selected 
the chemical substances considered in the course 
chiefly on account of their medical interest. A 
novel feature in the work is the postponement of 
the consideration of nitrogenous compounds to 
the last third of the book. In spite of the con- 
densation necessary in the circumstances, the 
author has succeeded in giving adequate ex- 
planations of several important and difficult sub- 
jects, such as stereoisomerism, the chemistry of 
the naturally occurring sugars, the cyanogen de- 
rivatives and organic amines, including alkaloids. 
In other shorter sections a more sketchy outline 
has been regarded as sufficient, but the subjects 
are always dealt with so suggestively that the work 
can be recommended as a useful introduction to 
the study of organic chemistry not only for medical 
students, but also for others requiring a general 
outline of the subject dealing with substances of 
practical interest. 
(4) An introductory course of quantitative 
analysis in which the author lays special stress 
on the speed with which analytical work should 
be carried out. Thoroughly practical directions 
NO, 2311, VOL. 92| 
are given for carrying out fifteen typical exercises, 
and the time required for completing these 
analyses is indicated in each case. The analytical 
processes are connected with the general chemical 
principles underlying these operations. For 
example, the precipitation of magnesium am- 
monium phosphate affords an opportunity for 
discussing the chemistry of phosphoric acid and 
its salts. In the separation of nickel and cobalt, 
considerable saving of time would be effected by 
substituting for the double nitrite method the 
processes based on the use of nitroso-8-naphthol 
or dimethylglyoxime. The appendix contains 
useful sections on the chemical balance, calibra- 
tion, electrolyte dissociation, and indicators. 
(5) This work is a valuable résumé from the 
pen of one whose name will remain inseparably 
linked with the subject of “Catalysis in Organic 
Chemistry.” The introductory chapter dealing 
with autocatalysis and negative catalysts is fol- 
lowed by sections devoted to the general survey 
of substances utilised as catalysts in organic 
chemistry, catalytic oxidations and hydrolyses, 
and the catalytic introduction into organic mole- 
cules of halogens, sulphur, metals, and the car- 
bonyl and sulphonic groups. Five chapters are 
devoted to the important subject of catalytic 
hydrogenation. Although the action of metals in 
accelerating the addition of hydrogen to organic 
and inorganic substances had been known since 
the commencement of the nineteenth century, the 
systematic study of this process, which.was first 
initiated by the author and Senderens in 1897, 
has since led to the development of a valuable 
general reaction in organic synthesis based on 
the employment of finely divided nickel. Due 
reference is made to the special processes of 
hydrogenation devised by Ipatieff, Paal, and 
Willstatter. The action of the metallic catalyst 
in inducing the reverse change of dehydrogenation 
has also been demonstrated by the author and 
by Zelinsky and others. In collaboration with 
Mailhe, the author investigated systematically 
the dehydrating action of the refractory metallic 
oxides (alumina, thoria, tungsten oxide, &c.), and 
laid the foundation of another general reaction 
in which the alcohols are converted inte’ un- 
saturated hydrocarbons. Conducted in the pres- 
ence of ammonia, hydrogen sulphide or organic 
acids, these dehydrations lead respectively to 
organic amines, thiols, or esters. Bearing in 
mind the author’s brilliant achievements in this 
field, his views on the mechanism of catalysis are 
of special interest. Whether occurring in homo- 
geneous or heterogeneous systems, catalytic 
change is regarded as being due to the successive 
a e 
