4 IVA TOL 
| NovEMBER I, 1906 
the labours of Ingen-Housz, and found that his real 
worth had not been recognised. Much information 
was gathered that showed how many-sided his activi- 
ties had been in science and in medicine, and Prof. 
Wiesner was induced by the meeting of the Inter- 
national Botanical Congress at Vienna to present the 
results of his labour of love in this volume. It must 
rank as a classic, admirable as a biography of a 
leader in research and as a history of scientific pro- 
gress in a most important field of study. 
Jan Ingen-Housz was born at Breda, in Brabant, 
South Holland, on December 8, 1730, and attended 
the higher school there until the age of sixteen, after 
which he continued his education in the Universities 
of Louvain, Leyden, Paris, and Edinburgh, even after 
he had graduated (at the age of twenty-two) in 
Louvain. From 1757 to 1765 he practised medicine 
in Breda, but, after the death of his father, he went 
to London, on the invitation of Sir John Pringle, the 
King’s physician. Here he became acquainted with 
distinguished anatomists and medical men, and 
made a study of the method of inoculation for small- 
pox. From London he went to Vienna, by the wish 
of the Empress Maria Theresa, and introduced the 
use of inoculation there. 
He frequently visited Switzerland, France, Holland, 
and England. For the last country he had an 
especial affection, regarding it as the land in which 
science was most honoured and furthered. He died 
in 1799, near London, while on a visit to the Marquis 
of Lansdowne. 
Ingen-Housz approached the research which has 
brought him most fame—the relation of plants to the 
atmosphere—from the standpoints of the physicist 
and chemist rather than the botanist, and with a 
view to the value of green plants exposed to daylight 
as purifiers of the atmosphere from the products of 
animal respiration. He had busied himself with the 
physical problems of electricity, magnetism, optics, 
and heat, and had made useful contributions to their 
investigation. His researches in chemistry led to 
improvements in the preparation of matches and in 
other matters of practical value. 
A very valuable advance in microscopical technique 
introduced by him was the use of a cover over the 
drops of water or other fluids in which the objects 
were included for examination. At first the 
were made of mica, but soon he employed thin glass 
covers, as is now the custom. 
His researches into the nutrition of plants were for 
the most part carried on during his stay in Vienna, 
although his first worlk on the subject was published 
in London in 1779 under the title ‘* Experiments upon 
Vegetables, discovering their great Power of Purify- 
ing the Common Air in the Sunshine, and of Injuring 
in the Shade and at Night.’’ It was soon 
German and Dutch translations. 
When Ingen-Housz began the researches that led 
him to such great results it was generally taught 
that plants extracted from the soil the materials of 
which they were in want in the conditions in which 
they exist in the plant, and that nothing of importance 
required to, or did, pass off from plants. That 
was given off had been determined by Priestley and 
NOV LOSiy VOL. 775\| 
covers 
issued in 
vas 
gas 
by Scheele, who had investigated the relations of 
green plants with the atmosphere; but Priestley 
arrived at the conclusion that these plants always 
freed the atmosphere {rom the ‘‘ fixed air ’’ (carbon 
dioxide) emitted by animals and emitted ‘* dephlogisti- 
cated air’’ (oxygen), and Scheele believed that they 
always added to the amount of the ‘‘ fixed air.”’ 
Ingen-Housz succeeded in showing that both these 
eminent chemists were right in part, the green parts 
in daylight emitting ‘‘ dephlogisticated air,’’ while 
parts not green at all times, and even green parts in 
darkness, emitted ‘‘ fixed air.’’ His 
views were combated, even Priestley joining in attack- 
ing them, and by his authority preventing their 
importance from being recognised as it deserved to be. 
The new foundation for chemical investigation 
afforded by Lavoisier’s discoveries was made use of 
by Ingen-Housz to explain more fully the nutrition of 
green plants than had been possible until the recog- 
nition of the composition of the ‘‘ dephlogisticated 
air’? and the ‘‘ fixed air,’’ and he showed that the 
carbon contained in plants is derived from the carbon 
dioxide of the atmosphere instead of from the soil 
as had been supposed by Senebier. He also showed 
that the carbon could be acquired by green plants only 
in light, and that carbon dioxide beyond a limited 
degree of concentration in the atmosphere proved 
harmful even to plants as well as to animals. He 
thus distinguished between the respiration and the 
assimilation in plants, a distinction not fully realised 
or taught by botanists until many years later. The 
value of humus and of vegetable manure as food for 
plants he ascribed, not to the substance being directly 
employed by the plants as food, but to its effect on 
the mineral contents of the soil, which were rendered 
more easy of absorption, and he demonstrated that 
diluted mineral acids produced similar beneficial 
effects. His later views on the nutrition of plants 
are given in ‘An Essay on the Food of Plants and 
the Renovation of Soils,’? which is contained in a 
collection of essays (in which it is No. 3) issued under 
the title ‘‘ Additional Appendix to the Outlines of the 
Fifteenth Chapter of the Proposed General Report 
from the Board of Agriculture on the Subjects of 
Manures,’’ London, 1796. 
An appendix stating the sources of information 
about Ingen-Housz, with extracts from letters and a 
bibliography of his writings, adds to the value of the 
volume, and supports Prof. Wiesner’s claim that he 
must be classed among the founders of botany, and 
that he showed singular ability also as an investi- 
gator in physics and in medicine. 
like animals, 
ANALYSIS OF PAINTS. 
The Chemistry of Paints and Paint Vehicles. By 
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HIS book or booklet is not intended to appeal to 
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facturer, but to the young analyst who has had little 
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indeed extremely limited, since it deals with the ex- 
